Substitute Obafemi Martins pounced on an 89th-minute defensive blunder to give Birmingham City a 2-1 upset win over Arsenal in a dramatic League Cup final on Sunday.
Arsenal had been overwhelming favourites to end their six-year trophy drought but a mix-up between defender Laurent Koscielny and goalkeeper Wojciech Szczesny allowed Martins to secure Birmingham's first major trophy since 1963.
Birmingham, battling against relegation from the Premier League, led with a header from towering striker Nikola Zigic but Arsenal equalised through Dutchman Robin van Persie and looked poised to win the first of the four trophies they are seeking this season.
"It feels like the greatest ever (moment), in terms of personal achievement, when you consider the team we were up against," Birmingham manager Alex McLeish said in a televised interview.
"We weren't given a prayer today and I said myself that Arsenal would win nine times out of 10. But we believed. It was a titanic performance."
Arsenal manager Arsene Wenger defended his 20-year-old goalkeeper Szczesny whose error contributed to Birmingham's winner.
"You have to be positive because he is a young boy," Wenger said. Hopefully he will pick himself up and respond well (in the FA Cup replay against Leyton Orient) on Wednesday.
"When we conceded the goal there was no time for us to respond.
"We have to pick ourselves up because the challenges ahead are massive. I wanted to end the wait (for a trophy) today. Now we will have to wait a bit longer."
Arsenal, who beat Barcelona in the Champions League last week and lie second in the Premier League, had an early let-off when Zigic played Lee Bowyer through and he was wrongly flagged for offside.
At the same moment, Szczesny clattered into Bowyer but instead of Birmingham being awarded a penalty and Szczesny a red card, Arsenal got a free kick.
Birmingham, far from being demoralised, settled quicker and buoyed by their vociferous supporters carried the game to Arsenal with Bowyer, former Gunner Sebastian Larsson and Keith Fahey looking for Zigic at every opportunity.
Arsenal, missing the guile of injured skipper Cesc Fabregas, also pushed forward with Jack Wilshere, Tomas Rosicky and Samir Nasri probing for the opening.
Nasri set up Andrei Arshavin for Arsenal's first real scoring chance when the stocky forward had time to turn and shoot and Ben Foster did well to save with his feet.
Birmingham, with 6ft 8ins (2.03 metres) tall Zigic as their target man, tended to go for the high ball and the forward's aerial power brought the opener after 28 minutes when he outjumped Szczesny to head his side in front.
Arsenal responded almost immediately when Van Persie headed over the bar but he was right on target 11 minutes later.
Wilshere unleashed a ferocious left-foot shot from the edge of the penalty area which smashed against the bar.
Birmingham failed to clear the danger and the ball came out to Arshavin who found Van Persie with a perfectly weighted cross for the Dutchman to volley crisply home.
Both sides attacked relentlessly in a superb second half, although Arsenal increased the pressure after Fahey shot against the post in the 57th minute.
Arsenal looked the more likely winners but with extra time looming Zigic flicked the ball on and Nigerian Martins, just six minutes after coming on to the pitch, took advantage of miscommunication in the Arsenal defence to stroke it into an empty net.