Tom Collins scored with the last play of the game to help Saints see off Wasps 27-23 in a pre-season friendly at the Ricoh Arena on Sunday afternoon.
In front of a decent following from Northampton, Collins was sent over in the corner after sharp set-up play from scrum-half Tom Kessell.
And Stephen Myler’s well-struck conversion wrapped up Saints’ second win in as many pre-season matches.
Wasps had competed well throughout, with their forward pack and winger Christian Wade causing plenty of problems.
But tries from Jon Fisher, Luther Burrell and Collins, plus the assured kicking of JJ Hanrahan and Myler ensured Jim Mallinder’s men sent their supporters home happy.
Saints had gone into the game having won their opening pre-season encounter, at Saracens, a week earlier, smashing Mark McCall’s men 36-17 at Allianz Park.
But they didn’t enjoy such dominance in the early stages against Wasps, who threatened through Wade, with Sam Dickinson making an important tackle on the winger.
Jimmy Gopperth did give the home side the lead just past the 15-minute mark, placing a well-struck penalty between the posts.
Saints didn’t take long to get level though, putting the pressure on Wasps at the breakdown and earning penalties that put them in position for a kick at goal,which Hanrahan made.
Wasps reacted with a flowing move that forced Saints into some last-ditch tackles, with the juggernaut that is Ashley Johnson chopped down on his way to the line.
The men in black did win a penalty though, and Gopperth did the business from the tee again.
Saints missed the chance to respond with a try as some fine work from Burrell and Jamie Elliott, who somehow kept the ball in play, was wasted by a knock-on.
Saints were hit with a blow when Calum Clark was forced off with his shirt being used to support his left arm.
Wasps were also hit by injury as a huge Dylan Hartley carry left George Smith needing to be stretchered off.
But the home side started to find some momentum late in the half, with a slick Rob Miller break and offload putting Saints in peril.
Lee Dickson was sin-binned for killing the ball five metres from his own line and Wasps won a string of penalties at the scrum.
But when the ball did come out, they fluffed their lines, throwing it out of play, with the referee’s whistle bringing an end to the half.
Saints started the second period with Dickson still off the field and Ben Foden at scrum-half, but they almost scored immediately.
A fast break from Foden and Elliott ended with Collins bundled into touch at the last, but Saints did get three points as Myler landed a penalty won at the scrum.
Dickson returned to the field with Saints having won the 10-minute period 3-0, but they were soon to find themselves behind again.
Teimana Harrison, on for Clark, knocked on in midfield and Wasps picked the ball up, sending it wide to Wade, who was tap-tackled by Collins but still wriggled over the line.
Gopperth added the extras with a tidy kick from the right touchline, but Saints issued an immediate riposte.
Myler kicked a penalty to the corner and the Saints forwards had too much muscle with Dickinson helping to push the powerful Fisher over the line.
The extras were added, and Saints were soon scoring again.
Burrell grabbed his second intercept try in as many games, diving over in delight, with Myler again notching the conversion with ease.
Gopperth narrowed the gap to four with a penalty before Saints emptied their bench, making eight changes at the same time.
And Wasps, who had been largely dominant up front, turned to their forwards to regain their lead.
After yet more scrum penalties, the home side drove their way towards the line, with Thomas Young scoring.
Replacement fly-half Ruaridh Jackson converted to give his team a three-point lead, but there was to be a sting in the tail for Wasps.
Saints cranked up the heat by kicking for the corner and Kessell picked up from the back of the drive to send Collins over in the corner.
Myler’s superb touchline conversion, amid some boos from the home fans, wrapped up another impressive pre-season success for Mallinder’s men.
Wasps: Miller (Stevenson 62); Wade, Daly, Macken, Tagicakibau; Gopperth (Jackson 62), Simpson; Mullan (c) (McIntyre 57), Johnson (Shervington 56), Cooper-Woolley (Swainston 57); Gaskell, Cannon (Rowlands 56); Jones (Rieder 55), Smith (Young 34), Thompson.
Saints: Foden (Tuala 60); Elliott (Packman 60), Stephenson (Eves 60), Burrell (Howard 55), Collins; Hanrahan (Myler 40), Dickson (c) (Kessell 60), A Waller (E Waller 60), Hartley (Haywood 40), Hill (Denman 50); Dickinson, Day (Woolford 60); Gibson (Nutley 60), Clark (Harrison 32), Fisher (Paterson 60).
Referee: Simon Harding