# Defensive Metrics: Pressures & Blocks · Football Level 8: Expert

Football · Level 8: Expert · Insporta Book (https://book.insporta.app/football/level-8/defensive-metrics-pressures-blocks/)

Defensive Metrics: Pressures & Blocks in Football (Level 8: Expert) on Insporta: 100 sourced facts behind 10 tests. Covers: tackles won, attempted and.

What defensive numbers record and what they miss: tackles, aerial duels, blocks, clearances, one against one defending, errors, xG against and the defenders in the record books.

## Test 1: Tackles won, attempted and by third

- A tackle counts whoever collects the loose ball; a tackle won means the tackler's side ended up with possession. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A tackle near one's own box stops danger; one high up the pitch starts an attack, so the location tells two different stories. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Tackles by forwards high up the pitch are the footprint of a team that tries to win the ball back early. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A defender targeted by the opponent's best dribbler makes many tackles; one who is avoided makes few, and may be better. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Set against the take-ons that got past him, tackles show how often he actually stopped the man in front of him. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A defender facing few attacks gets few chances to tackle, however good he is at it. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Centre-backs who defend forward, stepping into midfield to meet a receiver, record more tackles away from their box. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Every tackle won is a tackle, and those in the attacking third are a subset of all tackles won. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- The tackle is won because the ball ends with the tackler's team, even though a team-mate picked it up. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Almost two of his tackles per 90 come in the defensive third, far more than anywhere else. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))

## Test 2: Aerial duels

- Both players are logged, one with a won aerial and one with a lost aerial, so the totals always pair up. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Against a side that plays long, a centre-back may contest ten headers; against a patient passing side, two or three. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Winning headers against centre-backs gives a direct team a way up the pitch from goal kicks and clearances. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A header won straight to an opponent is logged as won, even though the team has lost the ball. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A lost header in midfield costs possession; a lost one in the box often costs a chance on goal. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Long balls and clearances create contested headers at both ends, so direct sides have the most duels in the air. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Corners and wide free kicks are decided in the air in the box, so his headers won there show what he does at dead balls. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- The higher and longer the ball, the more likely two players meet it in the air. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- The aerial duel is logged for both players, and the loose ball that follows is a separate contest. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Aerial duels are recorded for both players, so the winner's gain is always the loser's loss. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))

## Test 3: Shot blocks

- Blocks record the ball hitting a player who stood in its way, split into shots blocked and passes blocked. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A team that blocks many shots is facing many shots; the blocks show bravery but also how often it is under pressure. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Arms away from the body can turn a good block into a penalty, so defenders tuck them in or put them behind the back. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Event data treats a blocked shot as its own outcome; it is not counted as on target because the goalkeeper was never tested. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- xG measures the chance at the moment of the shot, before anyone blocks it, so the block does not change its value. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A defender who stands in passing lanes and gets a touch on the ball is credited with a pass blocked. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A side under heavy pressure blocks a lot, but the shots that get through come from the same close-range positions. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Shots off target are the most frequent of the three outcomes, blocks come next, and roughly one in ten shots becomes a goal. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Getting across the line of the shot before it is struck is what turns a chance into a block. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A defender who stands in the path of a shot and stops it is credited with a block. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))

## Test 4: Clearances

- A clearance is logged when a defender kicks or heads the ball away without aiming at a team-mate. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Teams that clear often are defending often and losing the ball straight after, which invites the next attack. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A side that keeps the ball under pressure would rather find a team-mate than kick it away, so its clearance numbers fall. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- An interception cuts out an opponent's pass; a clearance sends the ball away from a threatening area. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Height and width give the team time to reorganise and keep the ball away from the dangerous central area. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Clearances off the line are logged as their own type, because they stop what would otherwise be a goal. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- If the opponent wins the loose ball each time, the clearance only postpones the next attack. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A header that drops near the six-yard line is as good as no clearance; one to the edge of the box is soon back in; a long, high ball to the halfway line takes longest to return, and play is live throughout. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- After a clearance the defence steps up together, so the opponent's second wave starts further from goal. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- The header is aimed away from danger rather than at a team-mate, which is a clearance. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))

## Test 5: One against one defending in the data

- It records the times a player facing a dribbler won the ball with a tackle. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Dividing successful tackles on dribblers by all the dribbles he challenged gives the share of one-against-ones he won. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A challenge lost is a one-against-one in which the dribbler got the better of him. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A rate answers whether he stops the winger when it matters, whatever the number of times he is attacked. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A defender who holds his position and forces the attacker wide or backwards may not win the ball himself, but the move goes nowhere. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Van Dijk went through the whole league season without an opponent completing a take-on past him. (Source: Opta Premier League data)
- Keeping one of the league's best dribblers quiet is worth more than good numbers against a winger who rarely takes anyone on. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Winning the ball is best, delaying and turning the attacker back is next, and being beaten is the failure. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Closing and showing him one way comes before the tackle, which is timed for the moment the winger commits. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Stopping a take-on with a tackle is logged as a dribbler tackled, which counts towards his challenge success. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))

## Test 6: Errors leading to shots and goals

- It is logged when a player's mistake, such as a slip, a poor touch or a bad pass, leads directly to an opponent's goal. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- An error that leads to a shot is recorded whether or not the shot goes in; only some of them become goals. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Benzema charged down his throw for the first goal, and Bale's long shot slipped through his hands for the third. (Source: Match reports (BBC Sport, UEFA, FIFA))
- They concluded he had been concussed after a clash with Sergio Ramos earlier in the match. (Source: Match reports (BBC Sport, UEFA, FIFA))
- Data collectors judge whether a mistake led directly to the chance, so the figures carry some subjectivity. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Ba collected the loose ball and scored; Chelsea won 2-0 and Manchester City went on to win the league. (Source: Match reports (BBC Sport, UEFA, FIFA))
- A forward's mistake leaves the whole team between the ball and goal; a keeper's or centre-back's leaves almost nobody. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- The closer to one's own goal the mistake, the fewer defenders are left to recover the situation. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Real scored in the 51st minute, Liverpool levelled in the 55th, and Bale scored in the 64th and 83rd. (Source: Match reports (BBC Sport, UEFA, FIFA))
- His mistake gave the ball to the opponent, who scored directly from it, which is exactly an error leading to a goal. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))

## Test 7: xG against as a team measure

- Goals conceded swing on opponents' finishing and goalkeeping; the chances a defence allows are what it controls. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Dividing xG against by shots against shows whether opponents are shooting from good or poor positions. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Plenty of low-value shots is the signature of a deep, compact block that lets opponents shoot only from distance. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A penalty is worth about three-quarters of a goal, so one or two can swamp the figure for the chances a defence allows. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Shots in the box are where most goals come from, so their number shows how often the defence is breached. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Conceding from corners is fixed with marking and delivery defence; conceding in open play needs changes to shape and pressing. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- xG for minus xG against is one of the best single predictors of a team's future results. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A defence decides how many shots it allows and largely where from; whether they go in also depends on finishers and the goalkeeper. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Volume, then quality, then luck, then the source of the chances: each step narrows down what needs fixing. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- B's opponents created 1.4 expected goals a match against it, clearly the most of the three. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))

## Test 8: Defenders in the record books

- Andrea Barzagli, Leonardo Bonucci and Giorgio Chiellini were the core of Juventus's run of Serie A titles. (Source: Match reports (BBC Sport, UEFA, FIFA))
- Van Dijk came close to becoming the first defender to win it since Fabio Cannavaro in 2006. (Source: Match reports (BBC Sport, UEFA, FIFA))
- Beckenbauer, playing as a libero for Bayern Munich, won it twice in the 1970s. (Source: Match reports (BBC Sport, UEFA, FIFA))
- Sammer won it after being named player of the tournament as Germany won Euro 1996, and after Dortmund's Bundesliga title. (Source: Match reports (BBC Sport, UEFA, FIFA))
- They kept four clean sheets, the last a 0-0 with Ukraine in the round of 16, and lost the shoot-out without scoring. (Source: Match reports (BBC Sport, UEFA, FIFA))
- Zaccardo's own goal against the USA and Zidane's penalty in the final were the only goals Italy let in. (Source: Match reports (BBC Sport, UEFA, FIFA))
- The back line of Tassotti, Costacurta, Baresi and Maldini let in 15 goals in the league that season. (Source: Match reports (BBC Sport, UEFA, FIFA))
- Beckenbauer first won it in 1972, Sammer in 1996 and Cannavaro in 2006. (Source: Match reports (BBC Sport, UEFA, FIFA))
- Milan's record came in 1993-94, Italy's in 2006 and van Dijk's in 2018-19. (Source: Match reports (BBC Sport, UEFA, FIFA))
- He was the first defender to win the players' award since John Terry in 2005. (Source: Match reports (BBC Sport, UEFA, FIFA))

## Test 9: Defending the box in data

- Shots from outside the box score rarely, so most goals come from inside it. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A defence that keeps shots to 20 metres and more concedes far fewer goals, even if it faces many attempts. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Every pass or carry by the opponent into the penalty area is an entry against, a measure of how often the defence is breached. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Packing the box forces attempts from range or through a crowd of defenders, both of which score rarely. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A shot from a few metres gives the goalkeeper almost no time to react, so its xG is the highest in open play. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A cut-back from the byline is aimed at runners arriving around the penalty spot, so a midfielder is sent to guard it. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Most goals come from players who arrive late and free; losing a runner is how a box is breached. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Each zone of the box is covered before the ball arrives, so the cross meets a defender wherever it lands. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- The far-post tap-in is inside the six-yard box, the penalty spot is 11 metres out and the edge of the box 16.5 metres. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Nearly every mark is well outside the penalty area, the pattern of a defence that protects its box. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))

## Test 10: What defensive numbers cannot see

- Event data records actions on the ball; stepping up in line with team-mates leaves no event unless someone touches it. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- The data records who touched the ball, not the marking plan, so a lost runner may never show up against the right name. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- A centre-back who moves his line into place prevents chances without ever touching the ball. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Knowing where all 22 players are at every moment shows spacing, cover and line height, not just the moments on the ball. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Numbers point to candidates; how he reads danger, covers and moves the line is judged by watching him. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- When he stands in the lane, the opponent passes elsewhere, and nothing about the pass he prevented is recorded. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- On-off figures capture what a defender adds to the whole unit, including the things no single event records. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Event data sees only actions on the ball; broadcast tracking adds the players on screen; stadium tracking sees everyone. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- Data narrows the list cheaply; video and tracking judge what data misses; a live visit comes last. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))
- The offside is logged against the attacker; the defenders' step up is invisible in event data because nobody played the ball. (Source: Football analytics literature (Opta, StatsBomb, FBref definitions))

Sources: IFAB Laws of the Game / FIFA & UEFA technical reports / Opta, StatsBomb and FBref definitions / club and analyst publications / peer-reviewed research

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