Saints were unable to back up their brilliant win at Leicester as they lost 36-29 at Wasps on Sunday afternoon.
Tries from Teimana Harrison and Api Ratuniyarawa kept the away side in contention at 21-17 down at the break.
But Wasps pulled away early in the second period before surviving a late scare to secure the win.
Tries from Alex Mitchell and Ahsee Tuala got nerves jangling for the men in black and gave Saints a try bonus point and a losing bonus point, but the fightback fell just short.
It was to be a ninth defeat in 11 league away matches for Saints, who will conclude their difficult campaign at home to Worcester Warriors on Saturday.
They had headed to the Ricoh Arena on the back of a fine 27-21 success at Welford Road little more than two weeks earlier, but they were brought back down to earth early on by Wasps.
And after a patient passage of play, the ball was worked wide to the right, where speedy wing Christian Wade found space to scoot over the line for his side's opening score.
Jimmy Gopperth converted and Saints were soon forced to scramble to stop their hosts scoring again.
And when the away side got some possession of their own, they used it superbly, with Cobus Reinach breaking the Wasps line before Harrison sprinted in for a score.
Stephen Myler converted to level the scores with 12 entertaining minutes having elapsed, but Wasps were back in front after Gopperth slotted a penalty won at the breakdown.
And the home side extended their lead as they used their lineout as a platform on which to build an attack that caught Saints sleeping as Elliot Daly exposed them out wide.
Gopperth missed the conversion but Wasps now had an eight-point lead, with Saints desperate to ensure they didn't let their hosts get too far ahead.
And after Myler booted the ball to the corner twice in quick succession, Saints struck, with powerful lock Ratuniyarawa using his sizeable frame to score.
Myler converted to cut the gap to a single point before Gopperth landed a couple of penalties to give his team their breathing space back.
But Myler responded with a penalty of his own on the stroke of half-time to set up an intriguing second period.
Luther Burrell was sent to the sin bin just after the restart as he was punished for what the referee and TMO deemed to be a trip on Wade.
And Wade was soon making him pay as he found his way over for his second try after some good work from full-back Willie Le Roux.
Gopperth converted and the advantage was now 11 points, leaving Saints with some rebuilding to do.
And they were unable to do it as, just after Burrell returned from the sin bin, Wasps found more space on the right and centre Juan de Jongh grabbed his team's bonus-point score.
Gopperth missed the conversion, but the game was now seemingly drifting away from Saints.
They had a chance to respond when Reinach sprinted over halfway, but he ignored the sup-port run from fellow pace ace Tom Collins and Wasps got back to force a knock-on.
But Saints did score soon after as the impressive Jamie Gibson did some great work down the right before offloading to Mitchell for the try.
James Grayson, on for Myler, converted and the gap was nine points with 15 minutes remaining - and that was down to just four points five minutes later.
Collins' lofted pass helped to create some space for Saints and Tuala finished well.
Grayson missed the conversion, but Saints had 10 minutes to find a try that would win them the game.
The next points were to go the way of Wasps though as Saints' indiscipline again came back to haunt them, allowing Gopperth to put another three points on the board for his team.
Wasps then thought they had put the game to bed after a fine finish from replacement Josh Bassett, but the score was ruled out for a high tackle from James Haskell in the build-up.
Saints kicked the resulting penalty into the home 22, but one last attack didn't pay off as Wasps held out and won a penalty before booting the ball out to seal the victory.
Wasps: Le Roux; Wade (Bassett 60), De Jongh, Gopperth, Daly (Lovobalavu 72); Cipriani, Robson (Simpson 60); McIntyre (Mullan 33), Taylor (Cruse 55), Cooper-Woolley (Moore 62); Launchbury (c), Rowlands (Myall 64); Willis (Haskell 55), Young, Thompson.
Saints: Tuala; Foden (c), Burrell (Collins 60), Francis, North; Myler (Grayson 55), Reinach (Mitchell 62); Waller (Ma'afu 60), Haywood (Clare 66), Hill (Painter 72); Craig (Moon 72), Ratuniyarawa; Gibson, Harrison, Eadie (Ludlam 67).
Referee: Matthew Carley