The video assistant referee (VAR) system was used to rule out a goal in the Champions League for the first time in Wednesday's last 16 game between Ajax and Real Madrid.

Ajax defender Nicolas Tagliafico appeared to have headed the Dutch side ahead on 38 minutes, but referee Damir Skomina disallowed the goal after Dusan Tadic was shown to be offside on replays.

Tadic was deemed to be interfering with Real goalkeeper Thibaut Courtois after the Belgian spilled a header at a corner and Tagliafico nodded in the rebound.

The system, widely used during last year's FIFA World Cup, and now called upon in most of Europe's leading leagues, is making its Champions League debut after it was introduced for this season's knockout stages.

VAR was initially set to be rolled out in the Champions League from the start of next season, but the decision to bring forward its use follows lobbying from top European clubs.