Nili Latu scored from the final play of the game to help Newcastle earn a fine 24-22 win against Northampton at Franklin's Gardens.
Sonatane Takulua's nerveless conversion secured the victory for the Falcons as they stole the win and left the Saints with a losing bonus point.
It was a fifth successive Premiership defeat for Jim Mallinder's men, who had looked set to win it after Dylan Hartley popped up with a second-half score.
Hartley's effort, added to Harry Mallinder's score, a penalty try and five points from the boot of Piers Francis, put Northampton 22-17 up with 10 minutes to go.
But Latu and Takulua combined to secure the win, adding to earlier tries from Sinoti Sinoti and Josh Matavesi and two conversions from Toby Flood, who was sin-binned during the first half.
Northampton thought they had scored after just 13 seconds, but Rob Horne's effort was ruled out as a knock-on by Ben Foden was spotted by the TMO.
The Saints continued to call the tune though, with some tidy offloading from Michael Paterson and clever side-stepping from Jamie Gibson catching the eye.
Newcastle were having to stand tall in defence, but poor handling from both sides was preventing any momentum.
That was until Northampton won a penalty, kicked to the corner and Harry Mallinder found enough space to dummy intelligently before racing in for the score.
James Grayson missed the conversion, sending it just wide of the right upright, and Newcastle soon responded as Sinoti wriggled over for a try.
Flood converted to put the Falcons 7-5 up with 25 minutes of the match gone and the visitors were soon flying forward again, with Sinoti setting up Matavesi for a fine score.
Flood converted, but he was to be sin-binned before the break, for collapsing a maul as the Saints were awarded a penalty try.
The home side thought they had scored again soon after, but the TMO deemed that Hartley hadn't managed to score, with the England captain coming agonisingly close.
That meant Newcastle enjoyed a 14-12 advantage at half-time and that was extended when Flood landed a penalty 10 minutes into the second period.
Northampton needed to respond and they did, with captain Hartley grabbing a key try for his team.
Francis, on for Grayson at half-time, landed the conversion to put the home side 19-17 up with 19 minutes to go.
Northampton were then denied by the TMO again as a Nic Groom knock-on was spotted at the breakdown, meaning Ahsee Tuala's effort was ruled out.
Francis was soon slotting a penalty to ease the nerves further, but Newcastle had the final say as Latu powered over and Takulua converted to win it.