Defending

Each defender is assigned a specific attacker to follow wherever they go, rather than defending a zone. Old-school but still used in certain situations, especially at set pieces. The problem: if your man drags you out of position, you create gaps. Zonal marking largely replaced it, but some managers still use man-to-man systems or hybrid approaches.

How close together a team stays when defending. A compact shape has small gaps between players and lines, making it hard for opponents to play through. When compactness breaks down - players drift, lines stretch - holes appear. Analytics can measure it by tracking the distance between the deepest defender and highest attacker, or the space between lines. Staying compact requires discipline and fitness.

A one-on-one contest for the ball between two players. Duels get split into aerial duels (headers) and ground duels (tackles, physical challenges). Duel success rate is a key metric for defenders and midfielders - it shows how often they win individual battles. Some leagues track them obsessively, and certain players like Casemiro and Van Dijk dominate these numbers.

Deliberately stepping up as a defensive unit just before a pass to catch attackers offside. Risky because mistiming leaves attackers through on goal. Requires the whole back line to move together on the same cue. Some teams use it constantly; others avoid it because one mistake is catastrophic. VAR has made tight offside calls more reliable, which should help traps, but marginal decisions still create controversy.

Positioning to help a teammate who's engaging the ball, ready to step in if they get beaten. The covering player provides insurance - if the first defender fails, the covering defender should be there. Good teams have layers of cover; poor teams have gaps. Centre-back partnerships are built on trust that your partner will cover you when you step out to press.