Premiership: Wasps 16-22 Harlequins
Wasps (6) 16
- Southwell, Varndell
- Robinson 2
Harlequins (7) 22
- Hooper, Brown, Wallace
- Evans 2
Leaders Harlequins made it 10 wins out of 10 in the Premiership with victory over Wasps at Adams Park.
Wasps dominated the first half but Matt Hopper scored the only try before the break as the visitors led 7-6.
Having displayed their defensive nous, Quins took control after the restart, Mike Brown and Luke Wallace finishing off sweeping moves by the visitors.
Hugo Southwell and Tom Varndell hit back with tries but Quins held on and were good value for the win.
The victory leaves Conor O'Shea's side nine points clear of Saracens at the top of the table and full of confidence for Friday's Heineken Cup clash with Toulouse, while Dai Young's team remain in ninth.
England centre Riki Flutey came back into the Wasps side after missing his side's previous two games while Ed O'Donoghue's start in the second row was the only change in the pack from the side that beat London Irish last weekend.
Harlequins were managing a number of injuries, with Tom Casson coming in for Jordan Turner Hall, lock Charlie Matthews replacing George Robson, captain Chris Robshaw starting at number eight in place of Nick Easter and Luke Wallace starting at seven alongside Mo Fa'asavalu.
But it was Harlequins who started the livelier, a driving move very nearly resulting in a try for full-back Brown, only for the television match official to rule the ball had touched the dead-ball line.
But Quins did not let up, outside-centre Hopper touching down under the posts after cute inside passes from Robshaw and prop Joe Marler, who was in rampaging mood in the loose.
Evans kicked the extras before Nick Robinson slippered over a three-pointer to settle the nerves and trigger a period of attacking intent from the hosts.
Scrum-half Joe Simpson spotted a hole on the fringes and went on a dart before being hauled down just short of the try-line and Robinson should have narrowed the lead with a penalty but hit a post.
While Wasps showed ambition in the first quarter of the game, their work was undone by handling errors and turnovers.
There followed a sustained period of forward dominance, during which Quins' young pack came under enormous pressure, but Wasps eventually gave away a penalty and the visitors were able to clear their lines.
Robinson did reduce the deficit with a penalty just before the break, but with their scrum and line-out creaking badly and Wasps dominating territorially, it was a miracle Quins were ahead at half-time.
Harlequins had their first dominant scrum just after the restart and it led to a penalty from Evans, after which the hosts continued to unravel.
Wasps' line-out was burgled, not for the first time, and Matthews went on a charge before Robshaw and Hopper displayed great hands to release Brown, who chipped through and touched down for his side's second try.
Soon after, open-side flanker Wallace went over in the corner after a mazy run from Evans and a deft cross-kick from Danny Care.
With 22 minutes remaining Hopper was sin-binned and Wasps made their numerical superiority count, full-back Southwell diving over in the corner after good work from Dom Waldouck.
Robinson rather scuffed his conversion attempt to leave his side trailing by 11 points, but a matter of seconds after Hopper returned to the fray, Varndell went slashing through the Quins defence after quick ball off the top of the line-out and touched down next to the posts.
Robinson, who has been in poor kicking form all season, hit an upright again with his conversion attempt from almost bang in front and O'Shea's side held on for their 14th win out of 14 in all competitions this season.
Wasps director of rugby Dai Young told his club's website:
"I think you could see why they are top. They had three opportunities and they took them all and it was a real case for us of not turning pressure into points.
"We had a lot of pressure in the first half and we didn't keep the scoreboard ticking and it cost us.
"That is what we have got to develop and that's what teams who want to be at the top have got to develop. You have to be clinical and ruthless and Quins had that today and that was the difference in the end."
Harlequins skipper Chris Robshaw told Sky Sports 2:
"Our defence has been spot-on this year. We had a couple of lapses towards the end, but the guys really fronted up today.
"It was about the squad. Some guys came in, the likes of Tom Casson and Charlie Matthews, and did exceptionally well, so we are very pleased with today's efforts.
"Last year, we struggled with that [finishing]. We were getting into the final third and weren't clinical enough.
"This year, it has been the other way around. We have really taken our chances. We are a year wiser and have a lot more patience with the ball."
Wasps: Southwell, Varndell, Waldouck, Flutey, Wade, N. Robinson, Simpson, Payne, Webber, Broster, O'Donoghue, Wentzel, Birkett, Everard, Hart.
Replacements: Taulafo for Payne (57), Lindsay for Webber (67), Castex for Broster (67), Jones for Birkett (57).
Not Used: Burton, Davies, Davis, Daly.
Harlequins: Brown, Stegman, Hooper, Casson, S. Smith, Evans, Care, Marler, Gray, Johnston, Vallejos, Matthews, Fa'asavalu, Wallace, Robshaw.
Replacements: Urdapilleta for Hooper (76), Monye for S. Smith (46), Lambert for Marler (70), Skinner for Fa'asavalu (57).
Not Used: Brooker, Sinckler, Browne, Bolt.
Sin Bin: Hooper (59).
Ref: Dean Richards (RFU).