Arsenal manager Mikel Arteta resisted the temptation to field his strongest side by selecting Kepa Arrizabalaga in goal ahead of David Raya.
It proved to be an ill-fated decision, with the keeper a central figure as Arsenal's hopes of winning that first trophy since 2020 were placed on hold.
He had already been shown a yellow card for an injudicious dash from goal that resulted in a foul on Jeremy Doku, but worse was to follow in the moment this EFL Cup final got away from Arsenal.
Rayan Cherki's cross should have been dealt with easily, but it slipped through the keeper's grasp, allowing Nico O'Reilly to get in ahead of Martin Zubimendi to score.
There was no way back for Arsenal once O'Reilly added his second, and the Gunners can have no complaints.
Arsenal played within themselves, showing a lack of attacking ambition until the closing stages when the game was lost.
Arteta's side are still in a superb position to win silverware, with a commanding lead in the Premier League and with the Champions League and FA Cup still in their sights – but there was no consolation here as they turned in a disappointing display.
