Explained: How and why VAR disallowed Croatia's equaliser vs Portugal with ball-chip data in FIFA World Cup match

Croatia thought they had found a crucial equaliser against Portugal in their FIFA World Cup knockout clash, only for celebrations to be cut short after the Video Assistant Referee (VAR) overturned the goal using semi-automated offside technology and ball-chip data.

The decision sparked debate among fans, with many questioning how the technology determined the offside offence. FIFA later released an explanation detailing how the system works and why Croatia's goal could not stand.

What happened?

Late in the match, Croatia found the back of the net after a flowing attacking move, seemingly levelling the score against Portugal. However, before play resumed, the VAR initiated a review for a possible offside offence.

Following a brief check, the on-field referee was informed that the goal should be disallowed after technology confirmed that the attacking player was in an offside position at the exact moment the pass was made.

What is ball-chip data?

One of the key components of FIFA's semi-automated offside technology is a sensor embedded inside the official match ball.

The sensor records the precise instant the ball is struck, generating hundreds of data points every second. This allows officials to determine the exact frame when a pass is played—far more accurately than relying solely on broadcast video footage.

By synchronising this information with player-tracking data, VAR can establish whether an attacking player was ahead of the second-last defender when the ball was kicked.

How does the technology work?

FIFA's semi-automated offside system combines multiple technologies:

• A sensor inside the official match ball that records the exact moment of contact.

• Multiple tracking cameras installed around the stadium to monitor every player's movements.

• Artificial intelligence that creates a three-dimensional model of player positions.

• VAR officials, who verify the automated findings before communicating the decision to the referee.

Rather than replacing human officials, the technology provides precise data to support faster and more accurate offside decisions.

Why was Croatia's goal ruled out?

According to FIFA's explanation, the ball-chip identified the exact instant the pass was delivered. At that moment, the player who eventually became involved in the attack was positioned beyond the second-last Portuguese defender.

Because the player later participated in active play by receiving the ball and contributing directly to the goal, the offside offence was confirmed under the Laws of the Game.

The decision was therefore based not on where the player finished the move but on their position at the precise instant the pass was played.

Fan reaction

The overturned goal generated significant discussion online, with Croatian supporters expressing frustration over another marginal offside call, while others praised the technology for delivering an objective decision.

Football analysts noted that although such calls can be difficult to accept emotionally, semi-automated offside technology has substantially reduced human error compared with previous editions of the tournament.

Growing role of technology

The FIFA World Cup has increasingly embraced technology to improve officiating. Alongside goal-line technology and VAR, semi-automated offside systems have become a regular feature at major international tournaments.

FIFA maintains that combining AI-powered player tracking with ball-chip data enables officials to make quicker and more consistent decisions while preserving the referee's final authority.

Croatia's disallowed equaliser against Portugal serves as another high-profile example of how advanced technology is reshaping modern football, where even the smallest positional advantage can determine the outcome of a World Cup match.