The Gunners profited from the misfortune of Maxence Lacroix.
Arsenal will face Chelsea in the semi-finals of the EFL Cup after overcoming Crystal Palace on penalties following a 1-1 draw in normal time.
The Gunners dominated in the first half of the only remaining quarter-final tie, but found Palace goalkeeper Walter Benitez in superb form.
Despite Palace improving markedly in the second half, Arsenal finally broke them down in the 80th minute when Maxence Lacroix inadvertently put through his own net from a corner.
Marc Guehi briefly spared his blushes when he levelled in the fifth minute of stoppage time.
Yet it more misfortune would befall Lacroix as he was the only player among 16 penalty takers to se his spot-kick saved, Kepa Arrizabalaga springing to his right to send Arsenal into a two-leg tie with his former club.
More to follow
