Jordon Ibe's first Premier League goal for Bournemouth condemned Arsenal to a 2-1 defeat, with Alexis Sanchez conspicuous by his absence.
Ibe's first strike for the Cherries in 46 Premier league appearances sunk the Gunners, who leaked two goals in five minutes in this turnaround defeat.
Callum Wilson's third goal in four league games had Bournemouth level after Hector Bellerin handed the visitors a lead they could only squander.
Bournemouth went out to as big as 28/1 for the win in Sky Bet's live odds after Bellerin's goal for Arsenal, who were as short as 1/5 to get the three points.
The Cherriers were 16/1 to win from behind in Sky Bet's pre-match betting.
There were two big RequestABet winners for Sky Bet punters...
- Ibe & Wilson to score and Dan Gosling & Granit Xhaka to be carded at 125/1
- Jack Wilshere, Gosling, Xhaka & Simon Francis to be carded at 100/1
Arsenal's defeat, and its manner, proved another blow to Arsene Wenger, with the Gunners boss now resigned to losing key attacker Sanchez in the January transfer window.
Manchester United appear ready to pip neighbours Manchester City to the 29-year-old's signature, with Arsenal already having confirmed he will not sign an extension to his Emirates Stadium contract that expires in the summer.
Arsenal are out to 6/1 in Sky Bet's odds for a top-four finish.
Post-match reaction
Arsene Wenger lamented two costly mistakes that extended the Gunners' winless run to five games in all competitions.
"I feel overall physically it was a tough game for us," said Wenger.
"It wasn't forced errors, just lack of decision-making.
"We haven't created enough with the possession we had. We weren't sharp enough to create chances.
"Once you're 1-0 up you should create more chances. It's very frustrating and very disappointing, a very disappointing result for us, especially when you're 1-0 up.
"We made mistakes in areas where you wonder where they come from."
Eddie Howe hailed Bournemouth's resolve in turning the game around as the Cherries climbed to 13th in the table.
"We had to do it again, do it the hard way; it's never easy against any team to come back from a losing position," said Howe.
"It's a great sign for us, it has built confidence.
"There's always a chance you can come back into a game but to come back and win, and against one of the top teams, that's another boost for us.
"But now we've got to keep the momentum going, we can't relax. That would be dangerous."
