A stellar set of replacements made the difference as Saints stretched their lead at the top of the Aviva Premiership to 13 points with a 17-13 win over Harlequins.
Tries from Samu Manoa, James Wilson and Tom Wood, on his 100th Northampton appearance, secured the Friday night success at Franklin’s Gardens.
Quins frustrated Jim Mallinder’s men for long periods, bossing possession, as they did in the meeting between the teams at Twickenham back in December.
But the introduction of players such as Wood, Alex Corbisiero and, in particular, Kahn Fotuali’i finally sparked Saints into life.
The home side weren’t able to put the gloss on a strong second-half spell as Quins stopped their hosts from earning a bonus-point score.
And in the end, the impressive Marland Yarde grabbed a last-gasp consolation for Conor O’Shea’s side.
But Saints had done enough for the win, taking another sizeable step towards a home play-off semi-final as they are now a huge 16 points clear of third-placed Saracens with six games to go.
The presence of so many England players has undoubtedly helped the champions’ cause during the Six Nations and Courtney Lawes and Wood were back in the squad after injury.
Lawes, who had not played since December 20 due to an ankle problem, was making his 150th appearance for the club and he led Saints out.
The home side were eager to put further daylight between themselves and Bath, and they were dominant early on.
The rocket launcher right boot of full-back Wilson caused early problems for Quins, but the visitors showed plenty of resilience in the opening 10 minutes.
They also looked sharp on the counter, with wing Yarde eager to make his mark, but the men in white were met with stubborn resistance.
Finally some respite arrived, but still Saints had to be wary with Stephen Myler doing some fine cover work to stop Yarde racing onto a kick ahead.
Saints were struggling to get into the game and Quins were soon celebrating after securing a scrum penalty.
Fly-half Nick Evans slotted it to finally put some points on the board after 27 scoreless minutes and Mallinder’s men were stung into life.
They responded four minutes later as Samu Manoa used an inexorable maul to score, with Myler’s conversion made good by a kind kiss from the right post.
Quins quickly narrowed the gap with another Evans penalty after Calum Clark was deemed to have offended at the breakdown.
It was turning into a scrappy game, with neither side able to take it by the scruff of the neck and referee Tim Wigglesworth frustrating the fans with his continual use of the whistle.
Yarde came close to scoring in the corner five minutes into the second half, but he was just bundled into touch in the nick of time.
Saints were craving some territory and the introduction of Corbisiero, Fotuali’i and Wood helped turn the tide.
After Wood trucked it up the middle, the ball went left and Wilson dummied superbly before diving over the line.
Myler again hit the woodwork with the conversion, but this time it stayed out.
Quins, having spent plenty of time on the front foot, were now under pressure and Kyle Sinckler didn’t help their cause with a no arms tackle on Manoa that earned the prop a yellow card.
The away side managed to hold out for a few minutes, but with Fotuali’i upping the tempo at every breakdown and the Saints forwards getting on top, they were soon beaten.
Another unstoppable drive from the pack saw Wood pop up for a try, celebrating his 100th appearance in style.
Myler missed the conversion, but with the gap 12 points, the home side pushed on in search of the prized fourth score.
However, it was to be Quins who grabbed a late bonus point as Yarde flew clear and deservedly earned some reward for his fine personal performance and the spirit shown by his team.
Ben Botica converted, but Saints could reflect on another job done at the Gardens.
Saints: Wilson; K Pisi, G Pisi; Stephenson, Elliott; Myler, Dickson (c) (Fotuali’i 45); A Waller (Corbisiero 45), Haywood (Williams 76), Denman (Mercey 60); Lawes, Day; Manoa, Clark (Dowson 60), Dickinson (Wood 53).
Replacements: Olver, Tuala.
Harlequins: Monye (Lindsay-Hague 56); Yarde, Hopper, Sloan, Walker; Evans (Botica 68), Dickson; Lambert (Marfo 72), Ward, Sinckler; Matthews, Robson (c) (Twomey 60); Clifford, Wallace, Talei.
Replacements: Buchanan, Shields, Trayfoot, Tebaldi.
Referee: Tim Wigglesworth