Wasps withstood an astonishing late blitz to overhaul Northampton in the Premiership. Wasps move up to third on the strength of a smart try by Danny Cipriani, the boot of Dave Walder and a defensive finale of epic proportions.
Outplayed in the first half, Northampton grew in stature going into the final quarter, and when Bruce Reihana's splendid long-range penalty from the left wing cut Wasps lead to five points, the Saints launched a full frontal assault.
During the final four minutes of the 16 added by referee Dean Richards, Northampton moved the ball through 30 phases, battering their way forward via first one wing, then the other.
Just when you felt Wasps would be out on their feet, Shane Geraghty fired a pass behind Chris Ashton and into touch. The roar would have seemed fitting at the end of a cup final.
The Northampton rugby director Jim Mallinder said: "We lost the game in the first half with poor set-piece play, too many penalties conceded and that was always going to be a struggle.
"It was a brave effort at the end. We didn't panic and got the bonus point. But we'll need to be considerably better against Munster in next week's Heineken Cup tie."
With regular fly-half Cipriani switched to full-back, Walder had the edge over visiting stand-off Geraghty, and rifled over four penalties to reward Wasps superiority for most of the first half.
Geraghty got the opportunity to reduce the arrears, but his 29th-minute attempt sailed across the front of the posts.
Wasps could have scored two first-half tries, Ben Jacobs knocking on and and Tom Varndell taking a wrong option. And it needed three Saints to haul down Paul Sackey in full flight.
Cipriani made no mistake on 37 minutes, however, when Ashton misjudged a high kick from Joe Simpson. Cipriani scooped up the ball and swallow-dived over on the left. A Geraghty penalty finally saw Northampton on the scoreboard, but they changed ends very much second-best.
Northampton thought they had changed the flow two minutes into the second half when Chris Mayor was first to Geraghty's clever chip. But the score was ruled out for a knock-on.
However, Wasps failed to heed the warning and two Geraghty penalties injected fresh belief into his team-mates. For a crucial spell, it was Wasps turn to defend, and when Walder's fifth kick at goal flew wide, you sensed home-based anxiety.
A fine Walder drop-goal calmed the nerves, but Saints believed they could still prevail, and it needed some sterling hits to deny the visitors.
Cipriani was floored helping stop Reihana, and limped off minutes later to have ice applied to a knee injury. His replacement, Lachlan Mitchell, was knocked out stopping Ashton's pacy break up the right, and needed seven minutes treatment before leaving the field on a stretcher, his neck encased in a collar.
Wasps rugby director Tony Hanks said: "Lachlan went straight to hospital as a precaution, and he was upbeat. He is a very brave lad. That defence at the end was tremendous because we kept our discipline and our shape. We were guilty of letting Saints take the reins in the second half, so the win was hugely satisfying."
Geraghty's fourth goal increased the excitement, Reihana's belter brought the atmosphere to fever pitch. But it was Geraghty's wild pass that ended a memorable siege.
Scorers: Wasps: Try: Cipriani. Penalties: Walder (4), Reihana. Drop-goal: Walder. Northampton: Penalties: Geraghty (4), Reihana.
Wasps: D Cipriani (Mitchell, 73, Hickey, 76); P Sackey, B Jacobs, D Waldouck, T Varndell; D Walder, J Simpson; G Bocca, R Webber (Lindsay, 73), P Vickery (c), G Skivington (Leo, 64), R Birkett, D Ward-Smith, S Betsen, J Hart.
Northampton: B Foden; C Ashton, C Mayor, J Downey, B Reihana; S Geraghty, L Dickson; R Dreyer (Tonga'uiha, 51), D Hartley (c), B Mujati (Bonorino, 51), I Fernandez Lobbe (Lawes, 51), J Kruger, P Dowson, M Easter, R Wilson.
Referee: D Richards (Berks).