Late-match goals are usually explained as physical decline. The sequence of degradation runs the other way, with judgement deteriorating before the ability to run does.
Football is a continuous decision task
A player is repeatedly scanning, predicting and choosing under time pressure while also executing technical actions. The cognitive component runs constantly rather than in bursts.
Sustained attention is metabolically demanding and degrades measurably over long periods of concentration. Football adds physical exertion to that demand rather than replacing it.
The result is a load on decision-making that accumulates independently of how much running has been done.
Scanning frequency falls before speed does
Players check their surroundings frequently before receiving the ball, and that frequency is associated with better subsequent decisions. It is one of the first behaviours to decline as a match progresses.
A player who scans less often receives with a poorer picture of what is around him, which produces slower and more conservative choices.
Those choices look like caution or poor form rather than fatigue, because the player is still moving normally.
Positioning errors are the visible symptom
Defensive structure depends on continuous small adjustments relative to the ball and to teammates. Each adjustment is a decision, and each is easy to defer when tired.
Deferred adjustments accumulate into gaps that were not there minutes earlier, and the gap is what an attacking side exploits.
The resulting goal is usually attributed to a lapse in concentration, which is an accurate description of a physiological process rather than a character judgement.
Fixture congestion compounds the effect
Recovery between matches restores physical capacity faster than it restores the cognitive component, particularly where travel disrupts sleep.
A squad several matches into a congested run can therefore test as physically recovered while continuing to make the errors associated with tiredness.
This mismatch is one reason physical readiness screening alone gives an incomplete picture of whether a squad is fresh.
Measurement is the unresolved part
Cognitive assessment tools exist and are used in some settings, but they add testing burden and are sensitive to motivation and familiarity.
Behavioural proxies drawn from tracking data, such as scanning rate or reaction to a turnover, are promising because they require nothing extra from the player.
Until those proxies are validated properly, staff are managing a form of fatigue they can observe in outcomes but cannot yet measure directly.