Saints suffered their first defeat of the season in controversial fashion as a last-gasp Billy Twelvetrees penalty gave Gloucester a 26-24 victory at Kingsholm.
Twelvetrees’ effort was the final kick of a frantic encounter, with Northampton aggrieved at referee Martin Fox’s decision to give the Cherry and Whites the chance to win it.
Fox awarded a penalty at the scrum after a number of resets, having already appeared to miss an offside from the kick off.
Saints had gone 24-23 up with seconds to go as George North’s brilliant burst helped tee up Jamie Elliott for a clear run at the tryline.
But Twelvetrees kept his nerve to add a penalty to his earlier try to ensure Gloucester claimed their first win of the season and Northampton’s unbeaten start came to an end.
Charlie Sharples, Twelvetrees and second row forward Elliott Stooke, plus eight points from the boot of Freddie Burns had put the home side in the driving seat late on.
But Elliott, who added to tries from Ben Foden and Samu Manoa, and Stephen Myler, with the conversion, looked set to give Saints the win before Fox handed Gloucester the game.
Jim Mallinder’s men had started the game well in the scrum, getting on the right side of the referee to win an early penalty.
And after clearing their lines, the green, black and gold cut through the home defence like a hot knife through butter, Foden cruising past the lethargic Akapusi Qera out wide.
Myler landed an easy conversion in front of the posts and Saints had a 7-0 lead inside the opening six minutes.
The natives were growing restless early on but they had something to shout about on as Burns edged a 14th minute conversion through the posts.
Saints were suddenly shedding penalties at regular intervals but Burns skewed one wide from distance.
The fly-half almost atoned for that error with an assist, but his superb grubber kick was horribly fumbled forward by Henry Trinder with the tryline beckoning.
Saints were struggling to relieve the pressure, though, and their task was made harder when Sam Dickinson saw yellow for taking James Simpson-Daniel in the air.
The away side did get out for a couple of minutes’ respite, camping on the Gloucester line, but failing to bludgeon their way through the home defence.
The Cherry and Whites crowd called for more attacking intent from their team, with a man advantage, but they were butchering opportunities all over the place.
No.8 Sione Kalamafoni was villified after failing to find Simpson-Daniel, who would have had a clear run to the line.
Saints, to their credit, had been defending manfully with 14 men and after Dickinson returned they won a penalty from Twelvetrees, which Myler kicked.
It looked like Mallinder’s men would hold a 10-3 lead into the break, but Sharples had other ideas, bursting over in the corner.
Burns missed the kick from wide to the right to leave his team behind, but they were soon in front as Myler invited pressure by failing to clear and Twelvetrees profited.
The centre took the ball on after a quick tap from Jimmy Cowan and beat the defence easily to score.
Burns made it 15-10 with a good conversion but Gloucester weren’t in front for long as Manoa, as he does so often, made the most of a lineout drive to dot down.
Myler made a tough conversion and Saints threatened to extend their lead, seeing juggernaut North pushed out of play by Sharples with the line in sight.
In what was turning into a see-saw encounter, Burns edged Gloucester back in front with a well struck penalty from out wide.
The No.10 missed an ambitious penalty attempt from inside his own half soon after but confidence was growing in the Cherry and Whites camp.
Burns fired a drop goal wide before another big try scoring opportunity went begging, with Saints holding out strongly on their own line.
But there was only so much of a battering they could take and after great work from Simpson-Daniel, Stooke picked up the ball and got himself on the scoresheet.
Burns missed the conversion, meaning it was a six-point advantage for his side heading into the closing stages.
Saints, though, thought they’d won it after North’s brilliant blast from inside his own half set them away and Elliott finished it.
Myler slotted the conversion to leave his team looking set to travel home with the win, but Twelvetrees had other ideas, keeping cool to win it from the tee.
Gloucester: Cook; Sharples (May 75), Trinder, Twelvetrees, Simpson-Daniel; Burns (Tindall 68), Cowan (Robson 75); Murphy (Thomas 67), Dawidiuk, Harden (Knight 67), Savage (c) (James 67), Stooke, Kvesic, Qera (Morgan 64), Kalamafoni.
Replacements not used: Britton.
Saints: Foden; Elliott, Wilson (G Pisi 46), Burrell, North; Myler, Fotuali’i (L Dickson 54); A Waller (E Waller 67), Hartley (c) (Haywood 73), Mercey (Denman 67), Manoa (Dowson 63), Day, Wood, Clark, Dickinson (van Velze 67).
Replacements not used: K Pisi.
Referee: Martin Fox