Harlequins 26-15 London Irish
Harlequins extended their lead at the top of the Premiership with victory over struggling London Irish in front of 82,000 at Twickenham.
Sale's win over Worcester on Friday put them one point behind Irish but the Exiles failed to respond.
Wet conditions produced a low-scoring first-half with kickers Nick Evans and Ian Humphreys sharing the spoils.
Danny Care's try saw Quins pull ahead and, despite Exiles' fightback, a late penalty try denied them a bonus point.
London Irish are now without a win in the Premiership in almost three months - their last coming in the 39-17 victory over Northampton on 6 October.
Quins' win leaves them five points above second-placed Saracens, who take on the Saints on Sunday.
Aside from some impressive early kicking out of hand by both stand-offs, the opening half was attritional and short on thrills at a rain-drenched Twickenham.
Evans opened the scoring on six minutes after Declan Danaher broke his bind at a scrum but, when Mike Brown was penalised for not rolling away, Humphreys squared the score soon after.
Evans doubled his tally after Max Lahiff went straight down under pressure from James Johnston only for Maurice Fa'asavalu to enter the ruck from the side at the restart.
Humphreys levelled again from in front of the posts, and with little in the way of running rugby, given the desperate handling conditions, Evans missed his third shot at goal.
The Kiwi was at fault minutes later when, after a great maul from Quins inside Irish's 22, he took the ball into contact and knocked on in Sailosi Tagicakibau's tackle yards from the line.
There followed three more attempts from the tee in the run-up to the break, two of them for Humphreys, but all were off target.
Evans righted his sights during the interval and made it 9-6 early in the second half but Exiles were level again after Ollie Kohn entered a maul from the side.
Care's determined finish saw him dive under three cover tacklers after Quins five-metre line-out allowed the England scrum-half to combine with Evans in midfield.
The former All Black's conversion made it 16-9 with less than half an hour to play.
Humphreys quickly pulled three points back but Quins soon re-established a seven-point advantage.
The Exiles brought on new signing Pat Phibbs at scrum-half and their tempo rapidly increased, along with their possession and territory.
It saw the deficit reduced to four again and, with Quins starting to make unforced errors, Irish began to smell an upset with their forwards in the ascendency.
But as Harlequins fought back the game came alive and culminated in a 19-phase move by Quins that ended with Phibbs yellow carded for knocking the ball out of Care's grasp short of the line.
Irish deliberately wheeled two five-metre scrums and referee Greg Garner ran under the posts for the penalty try.
The score denied Irish the vital point and Evans's conversion completed their misery.
LINE-UPS
Harlequins: Brown; Williams, Hopper, Casson, Monye; Evans, Care; Marler, Gray, Johnston, Kohn, Robson, Fa'Asavalu, Robshaw (capt), Easter. Replacements: Buchanan, lambert, Collier, Matthews, Guest, Dickson, Botica, Lowe. London Irish: Homer; Ojo, Joseph, Tagicakibau, Yarde; Humphreys, Allinson; Lahiff, Paice, Aulika, Evans, Garvey, Danaher (capt), Sinclair, Hala'Ufia. Replacements: Lawson, Yanuyanutawa, Halavatua, Skivington, Gibson, Armitage, Shingler, Phibbs.