Saints made the most of a favour from old foes Leicester Tigers as they walloped Wasps 29-6 and advanced to the semi-finals of the LV= Cup.
A debut try from Samoan full-back Ahsee Tuala, plus further efforts from Phil Dowson, Jamie Elliott and the impressive Kahn Fotuali’i secured the final-four berth.
Saints had needed a favour from Tigers and Richard Cockerill’s side didn’t disappoint, securing a huge 43-9 win at Cardiff Blues.
That meant Northampton needed to score at least two tries and secure a victory, which they did with consummate ease.
Wasps enjoyed plenty of possession in the first 40 minutes, but only had two Alex Lozowski penalties to show for their efforts.
And Saints made them pay with a clinical display that also included some confident kicking from young fly-half Sam Olver, who registered nine points.
Tuala, who arrived from New Zealand as injury cover for Ben Foden, got things up just eight minutes into his first appearance in green, black and gold.
After Lozowski had given Wasps the lead from the tee, the new Northampton full-back dotted down in the corner following some slick work from centre Tom Stephenson.
Olver struck the conversion superbly from the touchline and Jim Mallinder’s men were up and running.
Wasps continued to enjoy possession, but Tom Varndell was wasteful as he eyed up the line before planting a poorly-judged grubber kick into the hands of the covering Elliott.
However, the men in white did earn something from another venture into Saints territory soon after, with Lozowski landing his second penalty of the match.
Olver quickly responded with an effort of his own at the other end and though Wasps were making plenty of the running, they were far from ruthless.
The same couldn’t be said for Saints as they scored their second try of the game three minutes before the break, with captain Dowson crashing over.
Olver’s conversion took the home side into a 17-6 lead and, with Leicester having humbled Cardiff, Saints knew a win would see them through.
And they quickly set about extending their lead after the break as a lovely chip ahead from razor-sharp scrum-half Fotuali’i bounced into the path of Elliott, who scored.
Olver missed the conversion, but Saints were cruising at 22-6 up and they soon had more to shout about.
Dom Waldouck flew towards the line, desperate to etch his name to the scoresheet, but after he was halted just short, Fotuali’i picked up to burrow over.
Olver added the extras and Saints were playing with a swagger, Fotuali’i opening the box of tricks and almost sending Ken Pisi clear.
The contest quickly petered out with both sides turning to their benches to give players some game time.
And Saints saw it out to secure a semi-final spot for the fourth time in six seasons.
Saints: Tuala; K Pisi, Waldouck, Stephenson (G Pisi 59), Elliott; Olver (Hooley 69), Fotuali’i (A Day 59); Corbisiero (E Waller 27), Williams (Haywood 54), Denman (Ma’afu 57); Ryder, Craig (Woolford 54); Dowson (c), Harrison (Nutley 57), Dickinson.
Wasps: Miller (G Hughes 56); Bassett (Eastwell 11), Daly, Helu, Varndell; Lozowski, Gash (Walsh 62); Yapp (McIntyre 11), Lindsay (Festuccia 50), Taylor (Cooper-Wooley 50); Rowlands (Myall 50), Cannon; Jackson (c), Young (Hughes 69), Thompson.
Referee: Steve Lee