While helping Rennes to victory over his former coach Unai Emery, the Frenchman was tickled by the Arsenal manager's manner.
Rennes forward Hatem Ben Arfa revealed the sight of "agitated" former Paris Saint-Germain boss Unai Emery made him laugh in the win over Arsenal.
Led by Ben Arfa, the Ligue 1 side ran out 3-1 winners in their Europa League last-16 first leg on Thursday, with Ismaila Sarr's late third goal putting Rennes in control of the tie heading into the return match.
The victory might have been particularly sweet for Ben Arfa, who was widely reported to have had a fractious relationship with Emery at PSG.
The former France international posted a picture of a birthday cake on social media after a year out of the team under Emery, while the player's solicitor revealed he was seeking a reported €8million in compensation for the lay-off.
Speaking after Rennes' victory this week, Ben Arfa, celebrating his 32nd birthday, said he was amused by the sight of Emery enduring a tough evening on the touchline.
"My motivation was to play a solid match, to win and get ourselves into a good position to go through," he told reporters. "That's what was in my head.
"But I did see the same Emery, as agitated as ever. I looked over at him a few times and that made me laugh a little. He hasn't changed.
"I told some friends before the match that my prediction was that we would win 3-1 or 4-1. We didn't manage to get the fourth but my prediction was right.
"Arsenal are still the favourites. We will have to score at least one, maybe two goals.
"To be the first team to beat Arsenal in France, we are making our own history. I'm happy and proud to make people happy [but there] is a return match."