Sergio Aguero's late breakaway goal earned Manchester City a first win at Arsenal for 36 years and a place in the Carling Cup semi-finals.
Park Chu-young and Alex Oxlade-Chamberlain tested City's goal in a first half the Gunners edged.
But although Edin Dzeko was off target on three occasions, the Bosnian helped create the winner on 83 minutes.
After an Arsenal corner, his pass set Adam Johnson free and he teed up Aguero to score his 12th goal of the season.
It was a cruel blow to the Gunners, who for much of the game looked the more likely winners.
However, the quality of the build-up to the goal, and the finish itself, made it a worthy denouement to a game which never really gained any true momentum.
Coming just two days after their 1-1 draw at Liverpool, City were often lacklustre, yet despite a much-changed side, it once again showed their expensively assembled strikeforce are able to find solutions where the rest of the team otherwise appear lost.
Former Gunner Samir Nasri was the only player to remain in the side from the trip to Anfield and he was given a torrid time from the start by the home supporters.
His side began the stronger, with Johnson firing just over when he cut in from the right on 10 minutes.
But although Arsenal also made 10 changes to the team which drew with Fulham on the weekend, they justified Arsene Wenger's pre-match comments that his youthful squad were capable of matching their more experienced opponents.
A minute after Johnson's strike, City's giant keeper Costel Pantilimon did well to save Park's close-range effort following Francis Coquelin's dangerous cross.
Pantilimon then tipped Oxlade-Chamberlain's 25-yarder round the post just before the half hour as Arsenal's impressive midfield turned the game in their favour.
City switched their formation in the first half as Aguero was introduced in place of the injured Aleksandar Kolarov.
But it did not stop Coquelin and the muscular Emmanuel Frimpong imposing themselves on central midfield opponents Nigel de Jong and Owen Hargreaves, who was making his third appearance of the season.
Allied to that industriousness, Oxlade-Chamberlain showed some neat touches and looked Arsenal's most dangerous player when he again cut in from the right to sting Pantilimon's hands.
Most of City's chances fell to Dzeko, who was their most productive outlet, yet City rarely reached the heights that they have done this season.
Visiting boss Roberto Mancini had complained about his side's lack of rest before the game, and City improved after the break, but the introduction of Gervinho after the hour mark gave more zip to Arsenal's attack.
Then, just as it looked as though the Ivorian might help eke out a winner, City scored a wonderful goal on the break which originated from an Arsenal corner.
Dzeko was the architect, speeding on to the loose ball to evade two challenges and picking out Johnson, with the English winger spinning on the edge of the box to set up Aguero for a well-taken finish from 12 yards.
Arsenal manager Arsene Wenger: "It was an unfair result but I felt we were a bit naive. I felt as well we did not take our corners very well but overall what is frustrating is that we lost a game we looked the winner of.
"We put a lot of effort in and are not rewarded. We lacked a little bit of experience to be decisive in the final third.
"I think in midfield (Emmanuel) Frimpong did well and (Francis) Coquelin did well. Sometimes you could feel in the final third we lacked a little in creativity - but overall we did well and I cannot fault the team. They did very well and showed heart, quality and desire."
Manchester City manager Roberto Mancini: "Samir Nasri can play better because he is a top player. Tonight is the first night he came back to Arsenal and it is not easy for a player that played here for four or five years.
"I think that he can improve a lot but it was the same situation with those who arrived last year, like Edin (Dzeko) and David (Silva).
"It (the win) is not important for him, it is important for the team. For him it is better than he played tonight so, when he comes back to play here in the league, he knows what will happen."