A last-gasp try from Nafi Tuitavake handed Saints a spirited 24-20 Anglo-Welsh Cup win at Sale Sharks on Saturday afternoon.
The Tongan centre eventually found a way through the Sale rearguard to hand his team the victory with the clock having hit 80 minutes.
It was a show of real character from Saints, who were 8-0 down at the break and 20-17 behind going into the final stages of the match.
The black, green and gold fought back thanks to two moments of magic from South African scrum-half Cobus Reinach, who helped to create tries for Ken Pisi and Ben Nutley.
James Grayson, on at half-time for Stephen Myler, added nine points in a flawless kicking display to help Saints secure their second win in three Anglo-Welsh Cup matches.
They continue to sit pretty at the top of Pool 3 and could book their place in the semi-finals with a win against Harlequins at Franklin's Gardens on Friday night.
Saints had named a strong side for the trip to Sale, but they were forced into a late change with George North withdrawing before kick-off and Tom Collins replacing him.
It was to be a lively start to the game, with Sale threatening first as Paolo Odogwu charged towards the try line.
But Nutley, playing at No.8, did well to stop the Sale wing at the second attempt, bundling him into touch to prevent the score.
Scrum-half Faf de Klerk was everywhere for the home side in the early stages, pulling the strings whenever his team got possession.
And Sale eventually broke the deadlock eight minutes before the break as No.8 Sam Moore stretched out to score.
Will Addison missed the conversion, but his team had a 5-0 lead and continued to play the game in the Saints half.
And after Addison made a break through the middle, Saints centre Tom Stephenson saw yellow for not releasing.
Addison made the most of the penalty to take his team into an 8-0 lead at half-time.
Saints were forced into a change at the break with Myler, who had been feeling his hamstring towards the end of the first half, replaced by Grayson.
Sale looked to make the most of their man advantage early in the second period, but it was Saints who would score first, and in some style.
Pisi led the charge, passing to Reinach, who sped forward before offloading to the Samoan wing for a brilliant breakaway try.
Grayson added the extras to bring his team to just a point behind at 8-7, and Stephenson then returned to bolster the away ranks.
And Saints were soon scoring another beautiful try as Reinach sped through Sale and kicked ahead for Tuitavake, who was brought to ground close to the line but passed to the onrushing Nutley, who powered over.
Grayson converted and Saints led 14-8, but Sale then started knocking loudly on the door as their fans finally lifted the noise levels.
A crossfield kick found the hands of centre Luke James and he was too strong for Saints' covering defenders, pushing his way over in the corner.
Addison missed the conversion to keep Saints 14-13 ahead with 20 minutes of the match remaining.
Grayson extended the away side's lead with a penalty, but Sale again refused to be deterred and they put the pressure on up front, turning the screw in the maul.
Saints were conceding penalty after penalty and eventually Sale made them pay, with Moore making the most of a big drive to the line to grab his second try of the game.
De Klerk converted to put his team 20-17 up with seven minutes remaining.
Saints pushed on in search of a response and Sale were forced to stand tall, with wing Josh Charnley doing brilliantly to stop Michael Paterson charging in for a try on the left.
The pressure was mounting on the home side and some brilliantly patient build-up play, Tuitavake eventually found a way over close to the posts to win it for Saints.
With the Sale fans flocking for the exits, Grayson put the icing on the cake for his spirited side.
Sale Sharks: Haley; Charnley, Addison (c) (Cliff 66), L James, Odogwu (Redpath 54); Wilkinson, de Klerk; Flynn (Pope 68), Jones, John; Evans (Postlethwaite 74), Beaumont; Ioane, Neild, Moore.
Saints: Tuala; Pisi, Tuitavake, Stephenson, Collins; Myler (Grayson 40), Reinach (Mitchell 77); Van Wyk (Ma'afu 54), Marshall (Clare 64), Brookes (Ford-Robinson 64); Ratuniyarawa (Paterson 61), Day (c); Ribbans, Ludlam (Wood 66), Nutley.
Referee: Greg MacDonald