Flimsy before halftime, fabulous by the end; Arsenal revealed the split personality that has undermined so many of their English Premier League title attempts as they snatched an unforgettable 3-3 draw at Bournemouth.
Out-battled for an hour by their modest south coast opponents, Arsenal belatedly sparked into life and Olivier Giroud's glancing header two minutes into stoppage time completed their remarkable recovery from 3-0 down.
It was the first time Arsene Wenger's side had recovered from such a deficit to draw in the Premier League and while they remained fourth, eight points adrift of leaders Chelsea who have played a game less, it could yet prove to be pivotal moment in their season as defeat would have been a hammer blow.
Swansea City's new manager Paul Clement was not officially in charge of his side's match at Crystal Palace but his presence helped the Swans move off the bottom of the table with a 2-1 victory at fellow strugglers Crystal Palace.
Stoke City also beat Watford 2-0 to leave Chelsea's match at fifth-placed Tottenham Hotspur on Wednesday the final instalment of a hectic fixture list.
The packed schedule over the Christmas-New Year period seemed to catch up with Arsenal who were back in action just 48 hours after beating Palace on Sunday.
They were second-best throughout the first half as Bournemouth moved 2-0 ahead after 20 minutes with a neat Charlie Daniels goal and a Callum Wilson penalty.
Ryan Fraser made it 3-0 in the 58th minute before goals from Alexis Sanchez and Lucas Perez set up a barnstorming finale.
Bournemouth were hanging on grimly after skipper Simon Francis was sent off in the 82nd minute but were breached again by a rampaging Arsenal side in stoppage time as Giroud pounced to follow up on his "scorpion" volley against Palace on Sunday.
"It was not a result we wanted before the game but at 3-0 down we'd have signed for 3-3," Wenger, whose side will slip out of the top four if Tottenham beat Chelsea, said.
"I believe we refused to lose. There's a great resilience in the team and we saw that today.
"Defensively we had some weaknesses tonight that were unusual and in some positions at the back we suffered."
Clement was named as Swansea's new manager shortly before they kicked off at Selhurst Park.
The former Bayern Munich assistant would have taken heart from the way his new club dominated the first half in which Alfie Mawson gave them a 42nd-minute lead and by the way they snatched a late victory through Angel Rangel.
Palace have now failed to win in their three matches under new manager Sam Allardyce and sit just above the bottom three in 17th place, one point above Swansea and Sunderland.
Like Wenger, Allardyce said the quick turnaround from playing on Sunday had undermined his side.
"Whether you're tired or not you have to play and I told them that at halftime," he said.
"I was baffled with our first-half display, we were lumping the ball to Christian Benteke and who told them to do that? They were confused."
Alan Curtis was officially in charge of Swansea but Clement came down to the dugout in the second half.
"He came down for some moral support, he made his presence felt at halftime, but there was not too much to say," Curtis said. "We would have surprised a lot of people with our performance today."
Ryan Shawcross and Peter Crouch scored either side of halftime for Stoke as they eased into mid-table.