Brighton 2 Arsenal 1
A grievance was handy to hide behind as Arsenal's problem with playing Brighton expanded to become a problem with this resumption.
Mikel Arteta, their manager, knew it too, accusing his team of "throwing the game away" before a melee on the pitch ticked another controversy box for the returning Premier League. Matteo Guendouzi, a real prospect in central midfield, led the quest for revenge against Neal Maupay, seizing him by the throat when Arsenal's second defeat in four days was confirmed.
In Arsenal's eyes, Maupay was doubly culpable: for challenging Bernd Leno in a way that may have contributed to his serious knee injury and then exposing them to the wrath of Highbury and Islington with the winner five minutes into added time.
Arsenal were nothing special, but they controlled much of this game and should have left sunny Brighton with three points. Their record against Graham Potter's team is dire. Brighton have now completed the league double this season against a club who may not see much of Europe next season, unless holiday restrictions lift.
Nicolas Pepe scored a sumptuous goal to put Arsenal in front and Guendouzi and Bukayo Saka carried the flag for a promising generation of youngsters.
Yet Arsenal crumbled when the game was theirs and their away record is abysmal: two wins in 15 league fixtures away from the Emirates. Those numbers point to serious quality and character flaws. A sense of injustice is all they went home with.
The sight of Leno being carted off will add to the angst around injuries, squad rebuilding and a dreadful start to the restart. Pablo Mari and Granit Xhaka both sustained ankle injuries in Wednesday's defeat at Manchester City. Lucas Torreira (ankle), Sokratis (thigh) and Calum Chambers are also unavailable while Cedric Soares, with a nasal fracture, is not expected to return until next month.
Leno had already left the pitch jabbing his finger at Maupay and seemingly promising further conversations. But the cold fact for Arsenal to digest is that Emiliano Martinez, his replacement, was assured, and in no way contributed to the defeat.
"I'd have taken three points at the start of the day, that's for sure," said Potter. "They [his players] found a solution, kept fighting, kept working, and we've got to recover because we've got a game on Tuesday [at Leicester]. We have talked a lot about how we keep going to the end and we got the reward today."
As for Maupay, Brighton's most persistent player, Potter said: "I like the fact that he works hard for the team. He's a good kid, he's learning, he's adapting to the Premier League from the Championship and I think he'll get better and better."
The goal by Pepe with which Arsenal took the lead in the 67th minute was a beauty and offered a glimpse of why Arsenal paid a club record £72m for him, even if the "end product" in his play is often missing.
The first 3.0 Premier League kick-off to be shown live on television in the UK boosted Brighton's chances of being in the top tier next season. It took them to 32 points with eight games left. They equalised through Dunk from a goalmouth scramble before Maupay endeared himself to Arsenal players by breaking into the penalty area to smash the winner past Martinez.
Maupay described his goal by saying: "It's a great ball from Alexis MacAllister. I left it - a great pass - and I just saw the keeper coming. I shoot with my left. It's a goal and I am so happy because it is our first win this year."
Arteta could see Guendouzi's anger stemmed from Arsenal missing chances and lacking conviction, four days after Luiz ruined their chance at Man City.
"Yeah it's the frustration because we threw the game away. I always believe players don't go out to injure [others]. We had more than one opportunity to put the game to bed so we cannot use that as an excuse."
Arteta was not hiding either from the effect this will have on morale: "Absolutely, when you lose two games the hardest thing is to lift the players up."