Chelsea produced a stunning late comeback to beat Arsenal 2-1 in the Premier League on Sunday, consigning Mikel Arteta to defeat on his home debut as coach of the north London side.
Four minutes later, Tammy Abraham settled a bad-tempered London derby when he drilled through Leno's legs.
Arsenal, 12th, started with great intensity, forcing Frank Lampard's tired-looking Chelsea back, until Aubameyang broke the deadlock after 13 minutes with an acrobatic header.
Lampard brought on Jorginho after 34 minutes and changed from a 3-4-3 formation to 4-3-3, as he did on Boxing Day against Southampton, and it helped the visitors find a foothold at a fired-up Emirates Stadium.
Fourth-place Chelsea, who lost five of their previous seven league games, had the better of the second half and when Leno blundered they quickly turned the screw to leave Arteta still hunting for his first win, following a draw at Bournemouth.
The hosts showed more spark than in recent weeks but could not capitalise and Jorginho's presence helped Chelsea turn the game around after the break.
"I give credit to the boys, credit to Jorginho," Chelsea striker Abraham said. "In the first 30 minutes they dominated the ball... then this man [Jorginho] comes on and it's a whole different ball game. Him coming on lifted us as a team."
Abraham saw one effort blocked and another saved by Leno in the second half, while Arsenal substitute Joe Willock fired narrowly wide.
Then with the clock ticking down Leno missed his punch as he tried to reach Mason Mount's free kick, allowing Jorginho a simple tap-in at the far post.
On Leno's error, Arteta said: "He will be down and when an error costs points it's harder. We have to respect what he's done at the club and get him back on board."
Abraham and Willian broke at lightning pace and combined for the English striker to net the second against a shell-shocked Arsenal, his 12th league goal of the campaign.
"He played well at Bournemouth and after he started to feel ill, and the last two days he's been in bed," Arteta said of the former club captain.
"I hope he doesn't leave."