Ashley Beck celebrated his 50th appearance for Warriors with a try but it was Northampton who gatecrashed the party with a bonus point win at Sixways.
Beck went over from a beautifully-worked move 16 minutes from time, a score that gave Warriors hope of claiming at least one point from the game.
Instead Northampton settled the match with a try from a driving lineout from replacement hooker James Fish and Warriors were left to reflect on a game of what-might-have-beens.
In Steve Diamond’s first game in charge, Warriors dominated for long periods, disrupted Northampton’s lineout and edged the scrums.
But Warriors struggled to convert pressure into points and defensive lapses proved costly as Northampton made most of their own opportunities, scoring three tries before the break.
Two of those tries came while Warriors were down to 14 men after Perry Humphreys was sin-binned for a deliberate knock-on.
Hooker Sam Matavesi was driven over from lineout that followed the penalty after Humphreys departed before scrum-half Alex Mitchell picked a hole in the defence where Humphreys would have been to score just before the wing returned to the fray.
Having dominated the opening 20 minutes without scoring a point, Warriors went behind to a try from centre Rory Hutchinson which Dan Biggar, a former team-mate of Beck’s at Ospreys, converted.
Fin Smith’s penalty three minutes later reduced the gap but the fly-half departed soon after with a head injury and Warriors were further disrupted when lock Andrew Kitchener suffered a similar injury.
A penalty from Biggar stretched Northampton’s lead to 19 points seven minutes into the second half but Warriors showed resilience by dominating the next 20 minutes.
Scrum pressure eventually told as Saints gave away a succession of penalties and British and Irish Lions prop Rory Sutherland drove over for his first try for Warriors.
Beck’s try four minutes later lifted the crowd and with Ted Hill, Kyle Hatherell and Duhan van der Merwe all battering away at the defence, Northampton were put under huge pressure.
But a penalty for obstruction when Warriors attacked down the left proved decisive. Northampton kicked the penalty to touch, won the lineout and rumbled Fish over for the try.
It was rare visit into Warriors’ 22 from Northampton after the break and gave a the final scoreline a look that did not reflect the balance of the game.
Warriors | 15 Billy Searle, 14 Perry Humphreys, 13 Francois Venter, 12 Ashley Beck, 11 Duhan van der Merwe, 10 Fin Smith (Williams 28), 9 Gareth Simpson (Chudley 55), 1 Rory Sutherland (Waller 61), 2 Niall Annett, 3 Christian Judge (Tyack 51), 4 Joe Batley, 5 Andrew Kitchener (Clegg 29), 6 Kyle Hatherell, 7 Ted Hill (C), 8 Matt Kvesic (Vailanu 51).
Replacements | 16 Beck Cutting, 17 Ethan Waller, 18 Jay Tyack, 19 Justin Clegg, 20 Sione Vailanu, 21 Will Chudley, 22 Owen Williams, 23 Alex Hearle.
22m | Hutchinson try 0-5
23m | Biggar con 0-7
25m | Smith pen 3-7
29m | Matavesi try 3-12
38m | Mitchell try 3-17
39m | Biggar con 3-19
47m | Biggar pen 3-22
60m | Sutherland try 8-22
64m | Beck try 13-22
70m | Fish try 13-27
71m | Biggar con 13-29