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. The Gunners kept pushing for an equaliser, with set-pieces looking to be one of their best chances of finding it, but Merino fouled goalkeeper Gianluigi Donnarumma from a corner in stoppage time to ease the pressure on PSG.
Arsenal's set-piece coach Nicolas Jover was furious with the decision to penalise Merino and started venting his frustration at the fourth official.
He was seen gesticulating on the touchline, and Arteta had to quickly step in to prevent him from getting into trouble as he had a stern word with Jover before pushing him back to the bench.
The final whistle went just seconds later, with Arsenal now facing an uphill task to reach their first Champions League final since 2006.
Jover has attracted plenty of attention since arriving at Arsenal in 2021 due to his tendency to stand in the technical area and give animated instructions when the team get a dead-ball situation.
Arsenal have become a feared team from set-pieces with Jover helping from the touchline, but his behaviour has not gone down well with everyone.
Back in December, Gary Neville branded Jover 'the most annoying bloke in football' after become irritated by the coach's antics.
His remark came during a watchalong when Arsenal beat Manchester United 2-0 at the Emirates, with both of the Gunners' goals coming from corners.
Jamie Carragher also took aim at Jover last week when Arsenal conceded from a corner in their 2-2 draw against Crystal Palace.
The former Liverpool defender highlighted after the game that Arsenal have conceded the second highest percentage of goals from corners in the top flight this season as he joked that Jover may need replacing.
'In terms of percentage, only Man United are worse than Arsenal set piece-wise this season. So when we make a big deal about the set-piece coach... he's absolutely out of this world in terms of going forward, but they've got a big problem defensively.
'So should we be cutting his wages in half? Do they need a defensive set-piece coach?
'It's been one of the stories of the season and rightly so. It's unbelievable. You feel like they are going to score a goal from a set-piece in every game, or come very close to scoring.
'Of course he's had a huge impact but it is funny that they are having huge problems themselves.'