Arsenal and Atletico Madrid played out a tense 1-1 draw, with both sides scoring from penalties in a game full of drama.
Viktor Gyokeres gave Arsenal the lead just before half-time after winning and converting a penalty. But Julian Alvarez equalised for Atletico early in the second half with a spot-kick awarded after a VAR review.
There was more controversy late on when Eberechi Eze appeared to win another penalty for Arsenal, only for the decision to be overturned after another VAR check.
Atletico pushed hard for a winner, with Antoine Griezmann hitting the crossbar, but neither side could find a second goal.
The result leaves the tie evenly balanced ahead of the second leg in London.
