A hair's breadth: Contentious offside decisions put focus on motion-sensing ball technology

Controversy clouded Croatia's exit from the World Cup on Thursday after their stoppage-time equaliser against Portugal was ruled offside by a literal hair's breadth — a decision that once again turned the glare on to sensors embedded in the official tournament ball that detected the apparent touch.

- HT Correspondent

Seconds before the final whistle, Croatian defender Josko Gvardiol prodded home an equaliser from an inswinging cross by Ivan Perisic. The goal prompted immediate recriminations from the Portuguese, who argued that Croatia's Igor Matanovic was in an offside position and had touched the ball as it floated through a crowded penalty box.

A check by the video assistant referee (VAR) and a pitchside review by referee Espen Eskas found Matanovic had touched the ball — likely with just the tip of his hair — contact confirmed by “Connected Ball Technology.” The sensor-based system is enabled by a 500Hz motion sensor chip that tracks the ball’s movement as well as any contact, however faint.

By the sternest interpretation of the laws of the game, any contact with the ball in an offside position is deemed illegal. That Croatia's last-minute reprieve was dismissed by a matter of microns sat well with few.