Mikel Arteta had to step in to calm down his set-piece coach in the closing stages of Arsenal's 1-0 defeat by PSG on Tuesday night.
Appearing in their first Champions League semi-final in 16 years, Arsenal fell behind early on to an Ousmane Dembele strike, but tried to work their way back into the contest and thought they had equalised early in the second half when Mikel Merino headed home Declan Rice's free-kick.
However, after a three-minute VAR review, Merino was adjudged to be offside and the goal was chalked off.