George Pisi grabbed a hat-trick as Saints slayed Saracens to book their place in the LV= Cup final at Sandy Park.
Jim Mallinder’s men earned a 26-7 success against their Aviva Premiership title rivals, setting up a clash with Bath or Exeter next Sunday.
Will Hooley slotted two penalties and Stephen Myler landed a drop goal and conversion to add to Pisi’s heroics as Saracens were put to the sword.
The away side had looked good for the win after dominating the majority of the first half, going in 7-6 up at half-time as Ben Spencer added the extras to Ben Ransom’s score.
Marcelo Bosch had an effort ruled out before the break and Saracens were eventually made to pay for not making their pressure count more emphatically as Saints came roaring back.
The green, black and gold have now claimed 13 successive wins in all competitions and know one more will ensure they claim the first piece of silverware on offer this season.
There was a frisson of excitement at the Gardens before the game and the atmosphere reflected it as Saints, who had opted to rest some first-team regulars, made a strong start.
Saracens were under pressure and were behind inside five minutes as Saints won a penalty at the breakdown and Hooley stepped up to land it with aplomb.
The home side were showing plenty of hunger in the opposition half and a huge rolling maul earned another shot at goal, with Hooley making it two from two.
The fly-half was soon forced to swap positions, moving to inside centre after Tom Stephenson limped off to be replaced by regular No.10 Myler.
And Saracens, who had taken time to get into the game, were soon in front as full-back Ransom skipped through the Saints backline, with Spencer adding the extras.
The scrum-half was an effective weapon with the boot when the teams met in the LV= Cup last month, but he was just off target with a penalty nine minutes before the break.
It was all Saracens, though, with Saints struggling to get out of their own half, and Bosch looked to have added another score to the visitors’ tally.
But the referee called on the TMO for assistance and it was deemed there had been a forward pass in the build-up.
Saints were lucky to only be one point down at the break, having been put under pressure for the majority of the first period.
They needed a boost after the break, but the second half started as the first finished, with Saracens showing their ability.
Just as the visitors had in the first half, though, Saints gradually pushed the opposition back, with the home fans urging them into Saracens territory.
A big lineout drive set up a chance for George Pisi to attempt to smash through the wall, and he did, putting his side back in front with a flying score.
Hooley took the kicking duties rather than Myler, pushing what looked a simple conversion wide of the right upright.
Both sides then called for some experience from the bench, with Charlie Hodgson one of four Saracens changes and Samu Manoa and Calum Clark thrust into the action for Saints.
And Manoa made an immediate impact, earning his side a penalty, with Myler using the freedom of the advantage to land a drop goal and extend the lead to seven.
Saints were a different side to the one who finished the first half and they grabbed another impressive score, created in Samoa.
Ken Pisi hared after a kick through to put Saracens under pressure and after Saints regained the ball, George Pisi jetted over in the corner.
Hooley missed the conversion, but, with 15 minutes left, Saints were 12 points up, sharpening their sights on Sandy Park.
But Hodgson had other ideas as he picked up a loose Manoa pass and raced towards the line, being denied at the last by a superb saving tackle from George Pisi.
And, fittingly, George Pisi has the final say at the other end, latching on to a clever inside pass from Kahn Fotuali’i to complete his hat-trick.
Myler put the seal on proceedings to leave the Saints fans singing ‘Can we play you every week?’ after a fourth successive win against Saracens.
Saints: Foden; K Pisi, G Pisi, Stephenson, Collins (Autagavaia 66); Hooley (A Day 75), Fotuali’i; E Waller (A Waller 50), Haywood (McMillan 65), Mercey (50), Craig (Manoa 57), C Day, Nutley (Clark 57), Dowson (c), Dickinson.
Saracens: Ransom; Tagicakibau (Wyles 65), Streather, Bosch, Wilson; Mordt (Hodgson 57), Spencer (de Kock 57); Barrington (Gill 48), George (Saunders 75), du Plessis (Johnston 48), Sherrif (Smith 57), Botha, Melck (de Jager 57), Hankin, Wray.
Referee: Leighton Hodges