Saints failed to replicate their Belfast brilliance as Nick Evans kicked Harlequins to a 18-9 victory at Franklin’s Gardens.
The English champions put in a stunning display to stop Northampton, who claimed a stunning 10-9 win at Ulster seven days earlier, getting up a head of steam.
Evans put in a polished performance, landing six kicks and pulling the strings at 10, while England full-back Mike Brown was a constant threat.
Saints could only reply through two penalties from Stephen Myler and one from Ryan Lamb after being denied a try in the first half as Foden’s score was pulled back for a forward pass.
It was another frustrating day at the Gardens, where Saints have struggled to break down the defences on occasion this season.
Saracens, Ulster and Harlequins have all left Northampton after stopping Saints scoring a try and the latest loss will have caused real anguish after such a good performance at Ravenhill.
There was a try poster placed on every seat in the Gardens before kick-off and the home side were desperate to maintain the momentum gained from their Heineken Cup victory.
Intensity was the buzzword, but Quins, boosted by big back-to-back wins against Italian minnows Zebre, got the scoring underway through an Evans penalty.
The Kiwi kicker was soon given the chance to extend his side’s lead to six from the tee, but his effort went to the left of the posts.
Saints were eager to get a foothold in the game and they levelled things up as the pressure game paid dividends and Myler landed a penalty.
Northampton were starting to whip themselves up into a frenzy and the home fans were on their feet as Ben Foden flew over the tryline.
But the full-back was denied a try as referee Barnes pulled play back for a forward pass, with a chorus of boos ringing round the ground.
And the murmurs of discontent reached a crescendo moments later as the man in yellow handed Quins a penalty and Evans put them back in front.
At the other end, Evans’ opposite number Myler was showboating, with some lovely offloads, including one between his own legs.
But Saints couldn’t break down the white wall erected by Quins and the champions lead 6-3 heading in at half-time.
Quins started the second half with desire and almost scored as No.8 Nick Easter put in a lung-busting surge towards the line, only to be halted by Foden and Elliott.
Evans was soon given the chance to add to his side’s tally with another tee kick, but he missed for the second time in four attempts.
Saints were having to defend for their lives, reminiscent of the scenes in Belfast seven days earlier and like the clash at Ravenhill, they were doing so with great effect.
Quins were soon forced back and forced into an error, leaving powerhouse prop James Johnston in the sin bin.
Saints were turning the screw, with Springbok prop Brian Mujati thrown into the action, and they soon got a penalty, which Myler slotted to level the scores.
Quins didn’t waste any time in getting their noses back in front, though, as Foden dallied on the ball, was closed down and conceded a penalty.
Evans was ice cool with the kick to make it 9-6 with little more than 15 minutes to go.
And he extended the advantage moments later, with a much easier attempt from in front of the posts.
Johnston was back on and Saints had lost the 10-minute spell the Samoan had been off the field 6-3, which won’t have pleased the home side’s coaching staff.
It was to get worse before the end as Evans made his fifth successful kick of the afternoon, booting Saints out of losing bonus point territory.
But Lamb, on for Myler, soon rectified that, bisecting the posts with a penalty to set up a huge final four minutes.
Fittingly, though, Evans had the final say as he stopped Saints securing anything from the game, with a penalty in front of the posts.
Saints: Foden; K Pisi, G Pisi, May (Waldouck 58), Elliott; Myler (Lamb 72), Dickson (Roberts 72); Tonga’uiha, Haywood, Doran-Jones (Mujati 53); Manoa, Lawes (Sorenson 70), Wood, Dowson, van Velze.
Replacements: McMillan, A Waller, Clark.
Harlequins: Brown; Williams, Hopper, Casson, Monye; Evans, Care; Marler (Lambert 69), Gray, Johnston; Kohn, Robson; Fa’asavalu (Guest 69), Robshaw, Easter.
Replacements: Ward, Collier, Matthews, Dickson, Botica, Smith.
Referee: Wayne Barnes