Stephen Myler's penalty with time up on the clock handed Northampton Saints a narrow 17-15 win over London Wasps.
Saints were given a wake-up call after last week's heroics against Leinster in Dublin, as they had to battle for victory at a blustery Adams Park.
Wasps thought they had won the game with three minutes to go, as Joe Carlisle's late penalty looked to have sealed a home win, only for Saints to secure a three pointer with the last play of the game.
After Elliot Daly had given Wasps early points, the Saints thought they had the lead when Luther Burrell picked up a bouncing ball to cross over, only for TMO David Sainsbury to rule out the score as Daly was pulled back by Christian Day.
Day made amends just a few minutes later, finding himself with the ball in hand as a Saints rolling maul crashed over the line. Jim Mallinder's men used the tactic to devastating effect in their game against their hosts last season, and were yet again dominating the home side physically.
Stephen Myler then secured his first points of the day for Saints, with Andy Goode then taking over from Daly to score two penalties in a row, giving Wasps a one point lead.
George North, moving into the centre alongside Burrell, was not quite as effective as the Saints would have hoped in the first half.
Despite Northampton's frustrations after a scrappy opening 40 minutes, they did head in with a narrow one point lead, knowing that the wind would be behind them after the restart.
Saints were laboured, but still held a lead going towards the hour mark, which was extended by Myler to create a five point gap.
Wasps kept pace, with replacement Joe Carlisle putting the visitors' just two points behind.
Tom Wood's sin-bin with ten minutes on the clock gave Wasps a chance to win the game with an extra man. They thought they had when Carlisle slotted through the posts giving Dai Young's men a 15-14 lead.
Straight from kick off though, Wasps' scrum was penalised, with Myler smashing over a tricky penalty to give Saints a last gasp victory.
Pens: Daly, Goode 2, Carlisle 2
Pens: Myler 4
Yellow Card: Wood
London Wasps: 15 Elliot Daly, 14 Will Helu, 13 Chris Bell (c), 12 Charlie Hayter, 11 Tom Varndell, 10 Andy Goode, 9 Charlie Davies, 8 Sam Jones, 7 James Haskell, 6 Ashley Johnson, 5 Joe Launchbury, 4 Tom Palmer, 3 Jake Cooper-Woolley, 2 Carlo Festuccia, 1 Matt Mullan
Replacements: 16 Tom Lindsay, 17 Taione Vea, 18 Phil Swainston, 19 James Cannon, 20 Guy Thompson, 21 Joe Simpson, 22 Joe Carlisle, 23 Andrew Suniula
Northampton: 15 Ken Pisi, 14 Jamie Elliott, 13 George North, 12 Luther Burrell, 11 Tom Collins, 10 Stephen Myler, 9 Kahn Fotuali'i, 8 Sam Dickinson, 7 Tom Wood (c), 6 Calum Clark, 5 Christian Day, 4 Samu Manoa, 3 Salesi Ma'afu, 2 Mike Haywood, 1 Alex Waller
Replacements: 16 Dylan Hartley, 17 Ethan Waller, 18 Tom Mercey, 19 Courtney Lawes, 20 Phil Dowson, 21 Lee Dickson, 22 Glenn Dickson, 23 Tom Stephenson
Referee: Matthew Carley
Assistant referees: Ashley Rowden, Peter Huckle
Television match official: David Sainsbury