The video assistant referee (VAR) system was used to rule out a goal in the Champions League for the first time in 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.
UEFA later confirmed why the decision was taken.
"The referee identified that Tagliafico's team-mate Dusan Tadic was in an offside position and interfering with the goalkeeper -- preventing him from playing or being able to play the ball -- as the header was being made," said UEFA on Twitter.
"This was in line with VAR protocol and the goal was correctly overturned and a free-kick given for offside."