|Wasps (13) 21|
|Tries: Wade, Cruse Con: Cipriani Pens: Cipriani 3|
|Harlequins (11) 24|
|Tries: Yarde, Walker Con: Smith Pens: Smith 4|
Wasps had England internationals James Haskell and Danny Cipriani sin-binned as they lost to Harlequins to end a run of 20 Premiership home wins in a row.
Christian Wade scored to put the hosts ahead but Haskell was yellow-carded after an altercation with Joe Marler.
Quins edged in front with the extra man when Mike Brown fed Marland Yarde for a try but Wasps led 13-11 at the break.
Charlie Walker went over for Quins, Tom Cruse replied and with the score 21-21 Marcus Smith scored a winning penalty.
It was the first time Dai Young’s side have failed to win at the Ricoh Arena in the Premiership since December 2015, when they were beaten by Saracens, as they set a club record of consecutive home league victories.
For John Kingston’s visitors it was a first away Premiership triumph since they won at Gloucester in March.
England and Lions flanker Haskell started on the bench on his return from finger surgery and had only been on the pitch for nine minutes when he was yellow-carded for grappling with his international team-mate Marler.
Smith kicked 14 of Quins’ points with Cipriani, who was sent to the bin on 66 minutes for an intentional knock-on, earning 11 points with his boot for the home side who move up to second with a losing bonus point.
Harlequins prop Kyle Sinckler also had to sit out 10 minutes of the match for illegally bringing down a Wasps maul, but the hosts did not fully capitalise on having a man advantage.
Wasps: Le Roux; Wade, Daly, Lovobalavu, Watson; Cipriani, Simpson; Mullan, Cruse, Cooper-Woolley, Launchbury (capt), Symons, Rieder, Thompson, Hughes.
Replacements: Johnson, McIntyre, Moore, Rowlands, Haskell, Hampson, Miller, De Jongh.
Harlequins: Brown; Yarde, Marchant, Roberts, Walker; Smith, Care; Marler, Ward, Sinckler, Merrick, Horwill (capt), Robshaw, Clifford, Luamanu.
Replacements: Elia Elia, Lambert, Collier, Glynn, South, Lewis, Swiel, Sloan.