Saints suffered last-gasp heartache at the hands of Newcastle Falcons again as Toby Flood kicked the winning conversion at Franklin's Gardens on Saturday afternoon.
After a prolonged spell of Falcons pressure after the clock had hit 80, Mark Wilson finally touched the ball against the base of the post and Flood did the rest to seal the 16-14 win.
Newcastle had won it from the final play of the game at the Gardens a year earlier, and they repeated the trick to claim a precious Gallagher Premiership win.
Saints had looked well on course to claim the victory after Cobus Reinach scored his second try of the match on 50 minutes.
But the Falcons kept fighting and after Brett Connon landed a huge penalty from close to halfway, tension levels started to rise.
Saints were suddenly under all sorts of pressure and Dan Biggar paid the price with a late yellow card.
And the Falcons forwards got the job done as Wilson snatched the vital score, with former Tigers fly-half Flood sealing a sweet victory that lifted his team off the bottom of the table.
It was the second time in as many weeks that Saints had lost to the team that went into the game propping up the Premiership standings, following the previous Saturday's loss at Sale.
And Chris Boyd's men are now in a precarious situation as they prepare to return to European action against the Dragons at the Gardens next weekend.
Saints had gone into the Falcons game in 10th position thanks to Bristol Bears' big bonus-point win against Leicester Tigers at Ashton Gate earlier in the day.
And after conceding a couple of avoidable early penalties, the home side, who started all of their returning international stars, went behind to a Flood penalty.
Saints responded with a prolonged period of pressure deep in Newcastle territory, but the home side simply weren't being clinical enough in the opposition 22.
Falcons, to their credit, were defending stoically, but they were being helped by mistakes from the black, green and gold, who were failing to find an effective final pass.
It was wave after wave of Saints pressure, but Newcastle were not fazed and when they finally got the ball, they forced infringements, with Flood adding a second penalty.
It was a shock scoreline considering the pattern of play and Saints finally rectified it, with Reinach spotting a gap, sprinting through it and beating a man to score.
Biggar, who was back from Wales duty, converted to give his team the lead their dominance merited and they had chances to extend the margin before the break.
But after Biggar twice kicked penalties to the corner with the clock having hit 40, Saints made a mess of a lineout and Falcons held out.
The second half started in scrappy fashion, but Saints stayed patient and after a brilliant break and perfectly timed pass from Teimana Harrison, the onrushing Reinach scored again.
Biggar easily converted from in front of the posts and Saints had the comfort of a 14-6 lead with half an hour to go.
There was little action for the next 20 minutes until Ahsee Tuala produced a superb try-saving tackle to stop Vereniki Goneva grabbing his customary try against Saints.
But the Falcons did get some points soon after as Brett Connon landed a long-range penalty with his first touch of the ball.
With nine minutes to go, nerves were jangling at the Gardens as Saints continued to search for the score that would put the game beyond their opponents.
Newcastle continued to come forward though and Saints stopped them from close range before holding the Falcons up over the line.
But after the clock hit 80, Biggar was sent to the sin bin and Wilson finished the job for his side, scoring the try that allowed Flood to convert with ease from in front of the posts.
Saints: Tuala; Kellaway (Sleightholme 68), Dingwall, Francis, Naiyaravoro; Biggar, Reinach; Waller (cc) (van Wyk 64), Hartley (cc) (Marshall 74), Hill (Franks 40); Ribbans (Ratuniyarawa 67), Lawes; Gibson, Ludlam, Harrison.
Newcastle Falcons: Hammersley (Connon 70); Goneva, Harris, Williams (Bettencourt 64), Sinoti Sinoti; Flood (c), Stuart (Takulua 58); Lockwood (Brocklebank 57), Cooper (McGuigan 50), Wilson (Mulipola 56); Green, Robinson (Davidson 40); Wilson, Hardie, Nagusa (Graham 67).
Referee: Matthew Carley