Harlequins will retain their position at the top of the Aviva Premiership table at Christmas after an 18-9 victory over Northampton at Franklin's Gardens.
Nick Evans kicked all Quins' points from the tee while Stephen Myler and Ryan Lamb responded for Saints, who were behind from the fourth minute.
Conor O'Shea's side have a point in hand over Saracens following Sarries' victory at Bath earlier on Saturday, while Saints slip down to fifth.
Harlequins' front row asserted their extra muscle early on, driving Northampton back 10 metres at the first scrum to earn a penalty, which Evans slotted to give the champions an early lead.
The stand-off missed soon afterwards though and Myler made him pay by levelling the scores on a pitch that held up surprisingly well given the recent torrential rain.
Ben Foden thought he had scored the opening try of the game but the touch judge ruled George Pisi's slap pass to the full-back was forward - although TV replays suggested otherwise.
To compound Saints' misery Myler missed a straightforward penalty soon after and Evans added three points from a similar position to make it 6-3 after 29 minutes.
And three minutes later Saints turned down a shot at the posts from 40m and kicked to the corner, only to see the attack come to nothing.
With incessant rain making handling problematic, a tremendous catch under pressure from Mike Brown allowed Nick Easter to sprint from one 22 to another, only for wing Jamie Elliott to gather his chip over the last tackler and a penalty ended the promising Quins break.
Evans missed another shot at goal and with 25 minutes to go prop James Johnston was sin-binned trying to kill a Saints break by lying on the ball on halfway.
Joe Marler was lucky not to get another yellow when he killed the ball in his 22, and Saints this time decided to kick for the posts with Myler making it 6-6.
Despite having the extra man the home side made little impression and two Foden errors cost them dear.
First, the England back dallied fielding a kick and was penalised for holding on to allow Evans to put Quins back into the lead.
The 27-year-old then spilled an up-and-under and a fifth penalty from Evans with seven minutes to go saw the home fans start to spill out of the ground.
Lamb came on to add a penalty as Saints decided against going for a try five metres from the line, but Evans denied them even a point with another successful kick right on time.