Harlequins extended their lead at the top of the Aviva Premiership with a 26-15 victory over struggling London Irish in front of a full house at Twickenham.

Scrum-half Danny Care's 52nd-minute try coupled with 16 points from his half-back partner Nick Evans' boot paved the way for Quins' ninth win in 12 league games this season.

Evans' opposite number Ian Humphreys kicked five penalties to keep London Irish in touch until the closing stages of a tight contest but the visitors left without a bonus point after conceding a late penalty try when down to 14 men.

The result puts Harlequins five points clear in the table, although Leicester and Saracens can both cut that gap when they play later in the weekend. London Irish remain second bottom, one point above Sale, who beat Worcester on Friday.

An early penalty from Evans opened the scoring but Humphreys soon responded in kind, a pattern that repeated itself to leave the scores level at 6-6 after 24 minutes.

Both sides struggled for fluency in tricky conditions, Evans and Tom Williams each fluffing their pass when Quins were well placed.

Evans missed a penalty chance on the half-hour and Humphreys was off-target twice in quick succession to bring an end to a forgettable half.

The kickers rediscovered their accuracy to exchange penalties early in the second half before England international Care wriggled over under pressure from all sides for the game's opening try - the TMO ruling he had just stretched far enough to get the ball down on the whitewash. Evans added the conversion.

Without threatening a try of their own, London Irish dragged themselves back into contention through Humphreys, who kicked his fourth and fifth penalties either side of Evans' fourth to cut the gap to 19-15.

But it was Quins was finished stronger and the pressure eventually told when referee Greg Garner lost patience with London Irish's regular infringements close to their own line - firstly sending replacement Patrick Phibbs to the sin-bin and then awarding a penalty try when a five-metre scrum was pulled down.