Anthony Gordon scored the only goal to end Arsenal's 10-game unbeaten start to the Premier League season.
The goal was thoroughly checked and improved by VAR after a triple assessment which took four minutes and six seconds to complete, with the ball possibly going out of play, Gabriel possibly being fouled in the build-up and then Gordon possibly offside when putting the ball in the back of the net.
Mikel Arteta was furious after the game, telling reporters: "It's embarrassing. That's how I feel and that's how everybody feels in that (dressing) room.
"You cannot imagine the amount of messages we've got saying this cannot continue. I feel sick. That's how I feel. I feel sick to be part of this."
Arsenal players have been silent since the game, until Sunday morning when Jorginho took to Instagram to post: "Proud of the team. Unacceptable what happened though. But we keep fighting."
The Gunners are next in action on Sunday when they face Sevilla in the Champions League.