Saints will be seeking revenge on the second day of the Premiership Rugby 7s series after losing to Wasps at Franklin's Gardens on Friday night.
The black, green and gold had earlier beaten Gloucester 22-20 thanks to Tom Emery's impressive late score.
And that means that despite the defeat in the second game, Saints will be in the cup quarter-finals on Saturday.
In the last eight, they will renew rivalries with Wasps (kick-off 2.30pm).
Newcastle Falcons will face Sale Sharks, Exeter Chiefs take on Saracens and Harlequins battle with Bath.
Saints started Friday's action by going behind against Gloucester inside two minutes as Aaron Hinkley scored for the Cherry and Whites.
Paddy Ryan levelled the scores, but Gareth Evans and Charlie Chapman went over in quick succession to put Gloucester 15-5 up at the break.
Hinkley added another score, but Saints then produced a stirring fightback.
Ollie Sleightholme's effort was followed by Josh Gillespie's score, which came after good work from Ryan.
And it was left to Emery to steal the show as the young full-back jinked his way through the Gloucester defence with just a minute remaining.
It was enough to seal the victory and sent Saints into the clash with Wasps, who beat Gloucester 33-7, with real confidence.
But the reigning champions proved too strong, securing a 35-7 victory despite an effort from Morgan Dayes.