Saints suffered late agony as Freddie Burns earned Leicester Tigers a 30-27 win with the last kick of the game in an enthralling east midlands derby.
Referee Wayne Barnes, who has attracted the ire of the Northampton fans in a number of recent derby matches, awarded a penalty for an offence by Courtney Lawes and Burns stuck the boot in to spark jubilant celebrations at Welford Road.
Saints had done superbly to battle back to 27-27, having been 21-0 down after three Tigers tries inside the opening 24 minutes.
Tries either side of half-time from Teimana Harrison and George North gave Jim Mallinder’s men hope and they thought they were ahead when Paul Hill burst clear to score.
But Barnes ruled Hill’s effort out after consulting with his TMO and deciding Tom Wood had made a high tackle on Peter Betham in the build-up.
Saints were 21-17 down at that point and two quick penalties from Freddie Burns put Tigers back in control before prop Dan Cole was sin-binned.
Saints desperately tried to fight back again, in torrid conditions and Jamie Gibson’s effort against his former club helped them do it.
Stephen Myler, on as a replacement for JJ Hanrahan, levelled things up with a penalty before Burns sealed the most dramatic of wins for Richard Cockerill’s team.
For Saints to even be in a position to take anything from the game was astounding after the start they had endured.
Tigers cut them apart inside just two minutes as a flowing move ended with Matt Smith dummying his way through the defence to score.
Owen Williams landed the conversion to make it a 7-0 lead and the men in grey had an early rebuilding job to do.
They responded by earning a penalty in Tigers territory, but it was to end in a bad miss by Hanrahan, who fired the effort wide.
Saints were enjoying some possession, putting pressure on the home side, but one potentially dangerous attack ended with a poor pass from North going out of play.
And it wasn’t long before Tigers started to turn up the heat again, kicking a couple of penalties to the corner and pushing Saints to breaking point.
Lachlan McCaffrey was the man who made it count on 21 minutes as he dotted down from a lineout drive, with Williams’ superb touchline conversion taking the score to 14-0.
Just three minutes later it was really starting to get ugly for Saints as the defence parted like the Red Sea and Williams waltzed in for his team’s third try.
The fly-half added the extras and it was already a long way back for the men from Northampton.
Wood came on for Sam Dickinson soon after, with the England flanker making his first appearance since November after returning from a shoulder injury.
Saints got some points on the board on 29 minutes as Hanrahan atoned for his earlier miss and they had some hope just before the break.
Hanrahan kicked a penalty to the corner and from the resulting lineout, Harrison drove over.
Hanrahan converted superbly from the touchline to cut the cap to 11 points going into the break, but Saints knew they would need a huge second-half showing to turn it around.
And they were to get exactly the start they wanted after the interval as Mike Haywood’s pass found North and the Wales wing sprinted from inside his own half to score.
Hanrahan converted and the away fans were in full voice, with their team having recovered from 21-0 down to get back to four points behind.
And Saints thought they were ahead on 52 minutes as prop Hill showed a great turn of pace to evade the chasing Leicester defence and dot down.
But referee Barnes penalised Wood for a high tackle on Betham in the build-up, meaning the try was disallowed and Tigers had a penalty.
They used it to earn territory and after Saints were penalised at a lineout, replacement Burns took the Tigers into a seven-point lead.
Burns soon stretched that to 10 with another well-struck effort, but Tigers were down to 14 men when Cole was sin-binned for a ruck offence.
Saints quickly cranked up the pressure, pinning Tigers back on their own line, but Victor Matfield was penalised for failing to release and the home side cleared their lines.
It wasn’t long before the dominance paid though as Gibson peeled off a maul and dived over for a try against his former club.
Myler, on for Hanrahan, converted and Saints were just three points behind with 12 minutes to go.
And Myler was levelling the scores four minutes before the end as Tigers were penalised for pulling down a maul.
But Tigers were to have the final say as Barnes awarded a penalty against lofty lock Lawes and Burns sealed the win with the last kick of a dramatic derby clash.
Leicester Tigers: Veainu (Harrison 72); Betham, Tait, Smith (Tuilagi 52), Thompstone; Williams (Burns 33), B Youngs; Ayerza (Mulipola 70), T Youngs (c), Cole; De Chaves (Pearce 77), Kitchener; Fitzgerald, O’Connor (Croft 6), McCaffrey.
Saints: Foden; Elliott, North, Burrell, Collins; Hanrahan (Myler 65), Dickson; A Waller (E Waller 65), Haywood (Williams 78), Hill; Lawes, Matfield; Gibson, Harrison (Day 65), Dickinson (Wood 26).
Referee: Wayne Barnes