Interim head coach Alan Dickens hailed Saints' for sticking with it after they scored late to sink Sale Sharks at the AJ Bell Stadium.
Nafi Tuitavake's try from the final play of the game provided a 24-20 victory in the Anglo-Welsh Cup clash.
Sale had taken the lead through Sam Moore's second try of the game, but Saints never gave up and they eventually got their reward.
Earlier tries from Ken Pisi and Ben Nutley brought the encounter to life after Sale had gone in 8-0 ahead at half-time.
And Saints kept battling as they took another giant stride towards a semi-final spot.
"It's an away victory and this is a tough place to come, whichever competition it's in," Dickens said.
"We made the point that they've only lost twice at home all season and we wanted to stay in the game.
"You're often on the wrong side of the penalty count away from home, and that was proved today, but credit to the players - we stuck in there.
"We scored a couple of breakaway tries and credit to the lads for finishing them off."
Cobus Reinach showcased his incredible speed as he helped to set up the first two Saints scores.
And Dickens added: "He's pretty sharp, isn't he?
"It wasn't just the speed of the break for the second try, he made a good decision to put it on his foot, Nafi Tuitavake picked it up and then there was fantastic support from Ben Nutley, who had run 75 metres to get on the end of it and score the try.
"It was a good counter-attack."