Arsenal's spluttering title challenge suffered another major blow as Mathieu Flamini's last-gasp own goal forced the Gunners to settle for a 2-2 draw against Swansea City on Tuesday.
Arsene Wenger's side looked set to bounce back from Saturday's humiliating 6-0 defeat at Chelsea after two goals in the space of 60 seconds midway through the second half from Lukas Podolski and then Olivier Giroud erased Wilfried Bony's early opener at the Emirates Stadium.
But Flamini deflected the ball into his own net from close range in the final moments to leave Arsenal six points behind leaders Chelsea with only seven games left.
That devastating setback may well herald the end of fourth-placed Arsenal's title bid and even their place in the top four isn't secure as fifth-placed Everton, currently six points behind the Gunners, have a game in hand and will host Wenger's team at Goodison Park in April.
While Swansea boss Garry Monk was pleased to escape with a point, he was furious with referee Lee Probert's decision to blow for full time with Jonathan de Guzman set to shoot.
"The players were magnificent but I spoke to the referee and told him it was a very poor decision. We were clean through on goal," Monk said.
Wenger added: "It is very disappointing but we have to take it on the chin.
"The spirit and effort were great but after getting to 2-1 we were too conservative. Our confidence level had been affected by Saturday's result."
Wenger had offered his flops a chance for redemption following the capitulation at Chelsea in his 1,000th match in charge and he made just two changes, with Thomas Vermaelen replacing the injured Laurent Koscielny and Flamini coming in for Podolski.
Kieran Gibbs and Alex Oxlade-Chamberlain were also available to start after the Gunners won their appeals against Gibbs' mistaken identity dismissal at Chelsea and the FA's subsequent attempt to punish Oxlade-Chamberlain for handball on the goal-line.
Oxlade-Chamberlain almost made the most of his reprieve in the opening moments when he seized on a poor headed clearance from Ashley Williams and fired in a fierce half-volley which was parried away by Michel Vorm.
Wenger had tried to remain upbeat after the Chelsea massacre, proclaiming "just because an accident has happened doesn't mean you are a bad driver".
But the Gunners were destined for another costly crash as Swansea took the lead in the 11th minute.
Vermaelen had lost his place after some shaky displays earlier in the campaign and, offered the chance to prove Wenger wrong, the Arsenal captain instead allowed himself to be exposed again when Neil Taylor advanced unchecked before swinging over a fine cross from the left.
Bony showed greater anticipation than Vermaelen and muscled his way in front of the Belgian centre-back to guide a superb header past Wojciech Szczesny for his 20th goal of the season.
Booed off at half-time, Arsenal desperately needed an early goal after the interval but there was no immediate improvement and Wenger sent on Podolski for Oxlade-Chamberlain.
The Gunners pushed Swansea to defend deeper as the half wore on and they finally equalised in the 73rd minute.
Gibbs accelerated past Angel Rangel to reach the touchline before clipping a perfectly-weighted cross back to Podolski, who volleyed home from close range.
Podolski wasn't finished yet and 60 seconds later the German surged away down the left and drilled over a low cross that French striker Giroud met with an emphatic finish into the roof of the net for his 19th goal of the season.
But Arsenal's capacity for self-destruction came back to haunt them in agonising fashion as Swansea equalised in the 90th minute.
With the points almost in the bag, Arsenal's statuesque defence allowed Leon Britton to play a one-two with Rangel on the edge of the penalty area and when the midfielder's shot was blocked by Per Mertesacker the ball cannoned off Szczesny and then onto Flamini, who unwittingly deflected it into his own net.