Ten-man Arsenal suffered their first away defeat by a French club in European competition in the first leg of their Europa League last-16 tie at Rennes.
The Gunners appeared to be cruising when Alex Iwobi’s early cross from the left drifted past home goalkeeper Tomas Koubek, into the right corner.
But Benjamin Bourigeaud’s stunning strike, which flew into the top right corner, levelled matters immediately after Sokratis Papastathopoulos’ dismissal for a second booking.
Unai Emery’s side fell behind when Nacho Monreal deflected Mehdi Zeffane’s cross from the right past his own goalkeeper Petr Cech.
And Ismaila Sarr’s diving header in the closing stages compounded a miserable evening for Arsenal.
However, it was no more than the hosts deserved as they capitalised on their man advantage to bombard the visiting goal after the break.
Arsenal will now hope to repeat their heroics from the last-32 stage, where they overturned a 1-0 first-leg deficit against Belarus side Bate Borisov to progress with a 3-0 home victory.