Wasps produced a late fightback to beat Harlequins 32-23 after Elia Elia was sent off in Chris Robshaw's Stoop farewell on Monday.
Former England captain Robshaw's last home game for Quins before he moves to Major League Rugby side San Diego Legion looked set to end in a victory, but Wasps turned it around to boost their chances of securing a Premiership semi-final spot.
Alex Dombrandt scored a double to give Quins a 15-8 half-time lead after a Tom Willis try put Wasps in front with 12 minutes gone in London.
Marcus Smith crossed early in the second half, having booted five points in the first, but Quins were a man down when Elia saw red for a tip tackle on Dan Robson 54 minutes in.
Gabriel Oghre crossed soon after for Wasps, but Smith's penalty gave the home side an eight-point advantage midway through the second half.
Wasps capitalised on their numerical advantage to win it late on, though, Thomas Young and Jack Willis crossing and Jimmy Gopperth taking his tally with the boot to 12 points as Lee Blackett's side moved level with second-placed Bath with one game of the regular season to play against Exeter Chiefs.
An emotional night at The Stoop as @Harlequins legend @ChrisRobshaw plays his final home game— Premiership Rugby (@premrugby) September 28, 2020
The hosts couldn't quite get over the line with @WaspsRugby striking late to pick up another valuable win
Who stood out for you tonight?#GallagherPrem #HARvWAS pic.twitter.com/JeOojBPsnE