Saints produced another stirring comeback as they claimed a 28-20 win at Kingsholm to secure their spot in next season’s Champions Cup.
As it was, Jim Mallinder’s men could have lost to Gloucester and still finished in the top six thanks to Exeter Chiefs’ sensational win at Harlequins.
But Saints, who had recovered from 14-0 down to beat Bath 15-14 a week earlier, wanted to finish the season in style, and they managed to thanks to a brace from George North and an early effort from George Pisi.
Stephen Myler added 13 points in a fine kicking display as Saints bounced back from a 20-8 deficit to secure a victory that earned them fifth place in the Aviva Premiership.
Gloucester had made the most of some slack defending during the first half as they scored through Lloyd Evans and Ross Moriarty. They also had two tries correctly ruled out.
But Saints showed their fighting spirit, with Harry Mallinder playing a key role in first-half scores for Pisi and North, who rounded things off with his second effort after the interval.
Mallinder’s side also stood up to some late pressure, showing a real desire to shut the Cherry and Whites out during the second period.
Saints had gone into the game knowing that a win would be enough to secure a top-six spot, but Greig Laidlaw put Gloucester in front with a penalty early on.
Things looked to have got worse for Saints soon after as the Kingsholm crowd were on their feet to acclaim a try from wing Elliott Creed, who was making his full debut.
But the score was ruled out as Creed had put a foot in touch before dotting down.
Gloucester were then penned in their own half for a prolonged period as Saints tried to forge an opening.
A couple of untimely knock-ons cost the away side, but they finally got the try they wanted - and it was a sensational effort, started by a superb break from Mallinder.
The young full-back cruised past a couple of players before offloading to Ken Pisi, who handed the ball to his brother, George, to score.
Myler missed the conversion and Gloucester were soon back in front as Laidlaw landed another long-range penalty following a breakdown infringement from Saints.
But the home side were soon down to 14 men as lock Tom Savage was sin-binned for a no-arms tackle on Lee Dickson and, from the resulting penalty, Myler put Saints in front.
Saints were still not in control of the game though and they struggled to get any territory while Gloucester were a man down.
And the sin bin period was to end in shocking fashion as Luther Burrell charged out of the line and Gloucester moved the ball wide to replacement Evans, who scored.
The flimsy defending was compounded by a successful convesion from Laidlaw, and Savage then returned with his team 13-8 up.
Saints’ defence was all at sea and Gloucester were starting to run through at will.
The home side soon had their second score as flanker Moriarty made the most of a couple more missed tackles to score.
Laidlaw converted to give his team a 12-point lead just before the break and the home fans were feeling confident about their side getting the bonus-point win they wanted.
But Gloucester were far from defensively sound themselves and Mallinder again played a huge part in a Saints score as his pass found North, who glided in unopposed.
Myler’s conversion cut the gap to five points at the end of an eventful half, and Saints were to go in front at the start of the second period.
Tom Wood was the architect as he picked the ball up from a ruck and charged through the gap before timing his pass to perfection for the onrushing North to score.
Myler converted to make it 22-20, and he was soon adding a superbly-struck long-distance penalty as the away fans lifted the noise levels.
Saints were really starting to get on top of their opponents and Burrell was starting to influence the game as his chase and hit forced a penalty.
The home fans didn’t like it, but Myler did, landing the kick to stretch his side’s lead to eight points with 25 minutes to go.
Dylan Hartley came on to lend a hand in getting his team over the line, with the England captain making his first club appearance since January 23.
And Victor Matfield and Kahn Fotuali’i were also introduced at various stages, making their final appearance in Northampton colours.
But Gloucester, who had enjoyed little territory during the second half wouldn’t give up and after Laidlaw missed a penalty, they put the squeeze on.
Jeremy Thrush thought he’d scored, but Gloucester were denied by the TMO.
Saints then proceeded to stand tall, showing their increased resilience since the interval, and they saw the game out to end the season in style.
Gloucester: Marshall (L Evans 19); Thorley, Twelvetrees, Atkinson, Creed; Laidlaw (c), Heinz (Braley 77); Thomas (Wood 57), Hibbard (Dawidiuk 57), Afoa (Doran-Jones 57); Savage, Thrush; Moriarty (G Evans 60), Kvesic (Rowan 65), Morgan.
Saints: Mallinder; K Pisi, G Pisi (Wilson 70), Burrell, North; Myler (Olver 77), Dickson (c) (Fotuali’i 63); A Waller (Ma’afu 63), Haywood (Hartley 63), Brookes (Hill 52); Lawes, Day (Matfield 58); Gibson (Nutley 73), Wood, Harrison.
Referee: JP Doyle