How Chip-in-Ball Technology Influenced Croatia's Controversial Offside Call Against Portugal

At the 2026 FIFA World Cup, Portugal narrowly defeated Croatia, finalists in 2018, with a late goal from Goncalo Ramos sealing a 2-1 victory. The match's final moments sparked debate when Josko Gvardiol appeared to score an equalizer for Croatia, only for the goal to be disallowed after a VAR review.

Why Was Gvardiol's Goal Disallowed?

In stoppage time, Gvardiol found the net, seemingly leveling the match. However, the referee consulted the video assistant referee (VAR) system and ruled the goal offside. The critical factor was a barely perceptible touch by Igor Matanovic, whose header redirected the ball, leaving Mario Pasalic in an offside position when the pass was made.

If Matanovic hadn’t touched the ball, Pasalic would have been onside because the original delivery came from deep on the left flank. The review then examined whether Portuguese defender Renato Veiga had deliberately played the ball when it deflected off his head. The referee concluded Veiga did not make a deliberate play but rather tried to avoid contact, so the offside call stood.

The Role of Connected Ball Technology in the Decision

The Adidas Trionda, the official ball of the tournament, incorporates advanced sensors known as Connected Ball technology. This system detects every instance the ball is touched. Initially, it looked like the ball never contacted Matanovic’s head, but the chip inside revealed otherwise.

The VAR display showed a waveform representing each ball touch, synced with video footage. A distortion in this waveform confirmed the ball clipped Matanovic’s head, adjusting the timing of the pass and confirming Pasalic’s offside position. This evidence led to the goal being overturned.

The technology resembles cricket’s Ultra Edge system that detects faint bat-ball contacts, offering precise detection beyond what the naked eye can see.

How Does Connected Ball Technology Work?

Developed by FIFA and adidas, the Connected Ball contains a small inertial measurement unit (IMU) sensor operating at about 500Hz, capturing data 500 times per second. It measures the ball’s acceleration and movements in three dimensions, identifying exact moments of contact.

This data streams live to the video operation room and integrates with player tracking systems from stadium cameras. Such information assists VAR officials with semi-automated offside calls by pinpointing the exact kick point quickly and accurately. It also helps analyze other key incidents, including handballs and penalties, improving the fairness and clarity of match decisions.

Kyle Bonn, a Syracuse University graduate with extensive soccer coverage experience, explains that this technology offers insights that enhance both refereeing and fan understanding of the game.