Didier Drogba grabbed both goals as Chelsea came from behind to win a Carling Cup final that ended in ugly scenes at the Millennium Stadium.
Theo Walcott gave Arsenal the lead after ghosting past Ricardo Carvalho.
But Chelsea equalised when Drogba was given the benefit of the linesman's flag to slot home and with six minutes to go he headed in a powerful winner.
A brawl erupted between the sides late on that led to dismissals for Mikel Jon Obi, Kolo Toure and Emmanuel Adebayor.
It was a disappointing climax to an intriguing final and cruel luck on Arsenal's young side, who dominated for large spells in the last League Cup final in Cardiff.
Arsenal's outfield players had an average age of less than 21 but they showed few nerves in producing some wonderful football before eventually running out of steam.
And they fell victim to the clinical finishing of Drogba, who scored his 27th and 28th goals of the season to again deny Arsenal manager Arsene Wenger a League Cup medal.
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It all looked so different early on as Chelsea's expensive line-up had few answers to Arsenal's dynamic midfield of Cesc Fabregas and Denilson.
The Blues had Petr Cech to thank in the 11th minute for a stunning save after Julio Baptista had drilled a shot through the legs of John Terry, who surprisingly overcame an ankle injury to play but ended the day in hospital.
Chelsea failed to clear the resulting corner and Walcott exchanged passes with Abou Diaby and glided past Carvalho before keeping his cool to slot the ball past Cech.
The 17-year-old could not have chosen a better time to score his first goal for the Gunners.
Chelsea equalised in clinical but controversial fashion in the 20th minute, with their first real attack on goal.
The Arsenal back line pushed up when Michael Ballack played a ball over the top for Drogba, who ran on to slip the ball under Manuel Almunia.
It was a split decision given in favour of the attacking player but Wenger spent much of the opening half displaying his anger at a linesman's failure to flag.
Arsenal continued to hit Chelsea from all angles and could have restored their lead just before half-time - but for a Carvalho intervention to deny Jeremie Aliadiere.
And the Gunners continued to look the more likely scorers after the break, with Diaby denied by Cech and Fabregas shooting just the wrong side of the post.
The Blues lost skipper Terry midway through the half when he took a boot in the face from Diaby as he tried to finish off an Arjen Robben corner.
Terry looked to be knocked unconscious and a mask was applied to his face to help with his breathing before he was carried off the field and taken to hospital.
The blow seemed to fire up his team-mates and they finished strongly and Arsenal's young legs began to tire.
Drogba had a shot well saved by Almunia and Frank Lampard produced a dipping long-range shot that smacked against the bar.
In the 84th minute Robben's cross picked out Drogba and he headed past a stranded Almunia.
Shevchenko could have made the seven minutes of injury time more bearable but his drilled shot thundered back off the bar.
The game ended disappointingly when Obi clashed with Toure and several players from each team, as well as both managers, got involved in an ugly scuffle.
Referee Howard Webb dished out three red cards as well as yellows to Fabregas and Lampard.
Over 11 minutes of added-on time was played before the final whistle was blown to hand the first major trophy of the season to Jose Mourinho's side, who are still in the hunt for three other pieces of silverware.
Chelsea: Cech, Diarra, Terry (Mikel 63), Carvalho, Bridge, Makelele (Robben 46), Lampard, Ballack, Essien, Shevchenko (Kalou 90), Drogba.
Subs Not Used: Hilario, Ashley Cole.
Sent Off: Mikel (90).
Booked: Essien, Carvalho, Diarra, Lampard.
Goals: Drogba 20, 84.
Arsenal: Almunia, Hoyte, Toure, Senderos, Traore (Eboue 66), Walcott, Fabregas, Denilson, Diaby (Hleb 68), Aliadiere (Adebayor 80), Julio Baptista.
Subs Not Used: Poom, Djourou.
Sent Off: Toure (90), Adebayor (90).
Booked: Denilson, Eboue, Fabregas.
Goals: Walcott 12.
Att: 70,073.
Ref: H Webb (S Yorkshire).
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