Saints overcame the dismissal of skipper Dylan Hartley to secure another magical east midlands derby win against Leicester Tigers at Franklin’s Gardens.
Jim Mallinder’s men played 63 minutes without Hartley, who was sent off for elbowing Tigers centre Matt Smith, and Jamie Elliott’s late score secured a stunning 23-19 Aviva Premiership success.
The Gardens erupted as Elliott dived over with three minutes to go, eliciting memories of Saints’ play-off semi-final win against Tigers in May, when Tom Wood scored in the same corner to book a place at Twickenham.
As on that occasion, when Salesi Ma’afu saw red in the second half, Saints were forced to do it with a man less, and do it they did - in some style.
Scores from Alex Waller, Ben Foden and Elliott got the job done as a penalty try and two efforts from Vereniki Goneva proved in vain for battered and broken Tigers.
And yet a Saints win had seemed so unlikely when the game reached boiling point 17 minutes in.
After one fight near halfway broke down, another erupted near the home line, and referee JP Doyle called for the TMO to sort things out.
With the referee happy to give a yellow for a Hartley elbow on Smith, the TMO recommended red and the Saints skipper was dismissed.
Some home fans clapped their captain off the field, others took to booing Doyle, and the jeers were to grow louder soon after.
Tigers attacked at the scrum and with Saints unable to resist on three occasions, Doyle went under the posts to award a penalty try.
Fly-half Owen Williams converted and his team had a 7-0 lead after 20 fractious minutes.
Things weren’t going to get any friendlier and Geoff Parling took Samu Manoa high, with Mike Haywood, on for Tom Stephenson after Hartley’s dismissal, doing well not to let his frustration get the better of him as he cleared the Tigers man out.
Saints used the penalty to get their first points on the board, with Stephen Myler slotting the kick with aplomb.
Mallinder’s team may have been a man down but they were determined not to be out of the contest and they put the pressure on Tigers, who were forced to defend for their lives.
The away side’s task was to get more difficult during the break as their man advantage disappeared for 10 minutes, with Tom Croft sin-binned for a high tackle on Ken Pisi.
Myler slotted the resulting penalty and Saints were desperate to maintain their momentum at the start of the second half, with numbers still equal.
And they did, with relentless pressure forcing Tigers to crack as the ball was flung wide to Waller, who finished with the kind of style more commonly seen from a flashy back.
The try had come at a cost, though, as Myler was injured in the build-up and James Wilson was forced to temporarily play fly-half, with Foden introduced at full-back.
Wilson missed the chance to add the extras to Waller’s score and Croft came back on, along with Myler, who was deemed fit enough to return.
But his first contribution after returning was a missed penalty attempt after Saints had smashed Tigers at the scrum.
Manoa was soon doing some smashing of his own, hammering flanker Julian Salvi and drawing gasps from the crowd as well as eliciting his trademark chant.
But Tigers were starting to gain some ground and after replacement Freddie Burns took them to within inches of the line, the ball went wide to Goneva, who scored.
Williams lashed the conversion wide and the away side held a one-point lead with 18 minutes to go.
But in a game that had everything, Saints were soon back on the attack, with Foden putting his foot to the floor and diving over the line to put his team back in front.
Myler again missed a tricky conversion from wide left and Tigers came roaring back once more.
A fleet-footed break from Miles Benjamin pushed Saints back and Tigers kept their composure to feed Goneva out wide once more.
Burns struck the conversion superbly to give his team a three-point lead with eight minutes to go and Saints could have been forgiven for feeling deflated.
But back they came, with Elliott bringing back memories of that magical May night as he dived over in the same spot at Wood had.
This time, Myler landed the conversion, with the roars from the home fans threatening to lift the roof off the Gardens.
And the noise levels were only going to get higher as Myler booted the ball out to secure another memorable Premiership win against the old enemy.
Saints: Wilson (Foden 56); K Pisi (Elliott 72), Stephenson (Haywood 17), Burrell, North; Myler, Fotuali’i (Dickson 62); A Waller (E Waller 62), Hartley (c), Ma’afu (Denman 52); Lawes, Day (Dickinson 62); Clark (Dowson 65)), Wood, Manoa.
Leicester: Tait; Scully (Benjamin 40), Smith (Burns 59), Allen, Goneva; Williams, B Youngs; Ayerza (Rizzo 59), T Youngs (Ghiraldini 44), Cole; Kitchener, Parling; Croft, Salvi, Crane.