Semi-automated offside scrutinised after Union Saint-Gilloise 2-3 OM in Champions League | OneFootball

Union Saint-Gilloise’s third goal against OM was cancelled by VAR for a few millimetres, reigniting debate around semi-automated offside in Tuesday’s 2-3 Champions League defeat. L'Équipe notes the system’s precision still provokes dissent.

Kevin Mac Allister thought he had levelled at 3-3 on 76 minutes, only for the technology to show his right heel marginally ahead of Emerson’s shoulder. Not visible in real time, the decision relied on the semi-automated set-up.

Coach David Hubert spoke of pride in his players yet frustration that a goal could hinge on millimetres when no advantage seemed gained. He lamented the pain of seeing such tight calls decide matches, while acknowledging his side still had chances.

The system was trialled in late 2021 at the Arab Cup and Club World Cup, then used by UEFA at the next summer’s Super Cup and in the 2022-2023 Champions League groups. It aims to speed decisions and resolve complex cases using multiple cameras, ball data and AI in a 3D model.

The engine refreshes constantly and flags potential offsides to VAR, who confirm line placement on frozen, modelled positions. In 2022 Pierluigi Collina stressed it is not robotic offside, with on-field officials still responsible for the final decision.

It is now in La Liga and the Premier League. Ligue 1 has not adopted it, partly for financial reasons, with VAR there still stopping the ball manually and using 2D images, which carries a wider margin of error. That margin might, in another world, have favoured Union.

Source: L'Équipe