Jorginho’s miscued back-pass left the out-of-position Kepa Arrizabalaga scrambling to parry off his own line, allowing Emile Smith Rowe to slot home the winner at Stamford Bridge.
Chelsea saw a Christian Pulisic effort chalked off for offside after a video assistant referee review, while Rob Holding escaped punishment for blocking Mason Mount’s shot with his hand on the goalline.
Arsenal boss Mikel Arteta hailed the Gunners’ first Stamford Bridge win in a decade, insisting his side have not given up hope of qualifying for Europe next term.
“It’s been 10 years since we’ve won here, so this is a really important result for the club, the fans and players,” said Arteta.
“The players showed how much they mean it, how much spirit and attitude there is in the group, and how much they care about it.
“Probably it is important to show it for the outside world, but they don’t have to show me anything about how much they care, how much they work and try. But probably for the outside, it was a big message.
“Europe is still mathematically possible, so we have to keep giving ourselves the last chance while it’s possible.”