When the killer blow for Arsenal came, with mere seconds of normal time remaining, it seemed somehow appropriate that it should be cloaked in black comedy. Three precious points appeared to be theirs and they stood not only to crown a fightback that had hardly been trailed, but to soothe the pain of the 6-0 humbling at Chelsea from last Saturday.
But Swansea City, and fate, had other ideas. When Leon Britton drove into the penalty area, after a one-two with Angel Rangel, Per Mertesacker dived in to challenge and briefly chaos reigned.
Mertesacker's tackle diverted the ball at Wojciech Szczesny and after it hit the goalkeeper it squirted back at Mathieu Flamini. Flamini, sliding towards his net, could do nothing as the ball ricocheted off him and trickled in for the most sickening of own goals. Everybody in red was gripped by that sinking feeling.
Arsenal's comeback had been fired by the substitute Lukas Podolski. He scored one goal and made the other for Olivier Giroud as Arsenal stood the game on its head inside 60 second-half seconds and looked set to banish the demons of Stamford Bridge.
Yet the late sucker punch seemed to catch the downbeat mood at Arsenal, the sense that their Premier League title challenge has come apart. It might have been even worse for them at the bitter end but for a refereeing decision that incensed the Swansea head coach, Garry Monk, and his players.
Jonathan de Guzmán was through on goal, being chased by Thomas Vermaelen and with Szczesny to beat, when Lee Probert decided to blow for full-time. Four minutes of injury time had been signalled and the game had entered the fifth but Monk argued that because the Flamini own goal had come virtually on 90 minutes, an extra minute over the four ought to have been added.
He also expressed his amazement that Probert should blow up when a major opportunity knocked. It was the first time in his career, Monk said, that he had seen such a situation. De Guzmán stuck the ball home, although both Vermaelen and Szczesny had stopped, and angry Swansea players surrounded the referee at full-time.
Monk's delight at the point that he would have taken beforehand, and also after Giroud's goal, was sorely tempered, and Arsène Wenger talked afterwards of how deeply the result had hurt.
He complained about a foul in the build-up to the Swansea equaliser and he took issue with Monk's argument about the De Guzmán controversy. Vermaelen, Wenger said, was in position to catch him. Nobody was happy. Arsenal have now drawn after each of their Premier League drubbings – Manchester City, Liverpool and Chelsea – but this one seemed like a defeat.
The main thing that has sustained Arsenal throughout the assorted pitfalls of their season has been the ability to beat the teams that they ought to be beating, namely those in the bottom half of the table. Not here and, as the dust settled, Wenger was more concerned with the threat to his club's top-four ambitions from Everton.
This was yet another occasion when Arsenal's nerves jangled and there was the collective offering-up of prayers from the home seats when Wilfried Bony flexed those mighty neck muscles to thump an early header down and into the near corner of the net.
The goal was the definition of simplicity. Neil Taylor ambled up the inside-left channel before hanging over a cross for Bony to attack. He beat Vermaelen to bring up his 20th goal of the season. The £12m invested on him last summer looks extremely smart. His all-round performance was immense. Monk described him as a "beast".
Arsenal had plenty of the game but they laboured for a cutting edge despite the best efforts of Santi Cazorla. He had the pick of the limited crop of first-half chances when he took a ball from Tomas Rosicky, skated past a couple of challenges and forced Michel Vorm into a save.
The home fans wrestled with a familiar internal struggle, between bellowing their backing and venting their angst. Every misplaced Arsenal pass, and there were plenty, drew howls, and there were loud boos at half-time. Swansea's centre-halves, Ashley Williams and Chico Flores, were excellent and as the second-half minutes ticked by, Arsenal stared disaster in the face.
The pendulum swung in what seemed like the blink of an eye. Wenger's team went from wondering where the inspiration might come from – with Aaron Ramsey, Jack Wilshere, Mesut Özil and Theo Walcott injured – to saluting Podolski's impact. Kieran Gibbs was the architect of the equaliser, accelerating past Rangel to cut back from the byline for Podolski, whose body shape was perfect to execute a difficult side-on volley.
Swansea lapsed again at the restart and, rather abruptly, another committed performance under Monk looked as though it would count for nothing. Angel gave away possession and when Cazorla nodded forward for Podolski, his cross was made to measure for Giroud.
The drama, though, was just beginning.