|Harlequins: (8) 20|
|Try: Alofa Pens: Evans, Swiel 4|
|Northampton: (6) 9|
|Pens: Myler 3|
A strong second-half performance from Harlequins secured victory against Northampton and saw them leapfrog Saints to go eighth in the Premiership.
Alofa Alofa's first try for the club and a Nick Evans penalty gave the hosts an early 8-0 lead.
Northampton pulled it back to 8-6 at the break through Stephen Myler's boot.
But Quins substitute Tim Swiel made an impact after replacing Evans, adding four penalties to Harlequins' tally, and Saints struggled to respond.
Northampton have recorded just two victories from their opening six matches and are ninth going into the European break, with Harlequins now a place and a point above them.
Saints arrived at the Twickenham Stoop having won the last seven encounters with Harlequins in all competitions but that never looked like happening this time around.
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Harlequins' performance was a physical one and at the heart were standout performances from props Kyle Sinckler, who was man of the match after a rumbustuous display, and Wales international Adam Jones.
When loose-head prop Mark Lambert left the field after just 10 minutes following a knock to the head, and with England's Joe Marler having pulled out prior to kick off, the pressure was on Jones - normally a tight-head - to deliver, and the veteran Welshman was more than equal to the task.
Evans landed a penalty to get the scoreboard ticking over for Harlequins but the former New Zealand fly-half went on to miss several shots at goal and was replaced at the break.
Shortly after the opening penalty quick hands produced the only try of the match as Alofa dotted down for his first score for the club.
After the opening quarter Northampton seemed to stir and, although they had limited possession compared to their hosts, Myler kicked two penalties to ensure the match was delicately poised 8-6 at the break.
Evans did not return for the second half, clearly still nursing the injury that had seen him on the side-lines in recent weeks, and Swiel took over at fly-half.
Northampton proceeded to regularly infringe and the South Africa-born Swiel made them pay, with his four penalties taking the match well out of Saints' reach.
Harlequins: Brown; Yarde, Alofa, Roberts, Visser; Evans, K Dickson; Lambert, Buchanan, Sinckler, Merrick, Horwill (capt), Robshaw, Wallace, Chisholm.
Replacements: Gray, Jones, Collier, Twomey, Luamanu, Mulchrone, Swiel, Marchant.
Northampton: Tuala; K Pisi, G Pisi, Burrell, North; Myler, Groom. A Waller, Haywood, Brookes, Lawes, Paterson, Wood (capt), Clark, Harrison.
Replacements: Clare, E Waller, Hill, Dickinson, Picamoles, L Dickson, Olver, Foden.
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