Wasps withstood a late fightback from rivals Leicester to secure a precious 24-22 Guinness Premiership victory at a packed Adams Park.
After the hosts had gone ahead through a Paul Sackey try, four penalties from Toby Flood put the Tigers in the ascendancy but Steve Kefu crossed to restore Wasps' lead at the break.
Dave Walder's solid kicking increased the advantage and Wasps hung on despite a last-minute try from Jordan Crane, which earned Leicester a bonus point to keep them ahead of their rivals in the table.
Given torrential rain overnight, Wasps were relieved they did not have the embarrassment of having to call off a home game, having refused to play at Sale's Edgeley Park on November 27 because they deemed the pitch unplayable.
Wasps face a hearing to discuss that situation on Monday.
However, on Sunday the buzz among their supporters concerned the return of Danny Cipriani, on the bench for the first time since suffering a broken leg on October 4 but unused.
But it was England team-mate Sackey who had them on their feet after six minutes, thundering up the right wing after snaffling a tapped penalty by Joe Simpson and smashing through three poor attempted tackles. Walder missed the conversion.
Leicester chopped off three of those five points when Flood made no mistake with a penalty, which was awarded for offside. And, following a sustained period of pressure, Flood was handed another opportunity to go for goal in the 16th minute when Serge Betsen offended at a ruck, and was again successful.
Wasps conceded another stupid penalty three minutes later for a collection of offences attempting to halt a Leicester driving maul. Referee Chris White warned he was losing patience but Flood's standing foot slipped and his penalty sailed yards wide.
The Wasps scrum was creaking under pressure, Tim Payne repeatedly going to ground. With 22 minutes gone, it went nose first again and Flood made no mistake this time, steering his penalty between the posts from 35 yards.
Wasps finally broke upfield from the restart and it was Leicester's turn to transgress, ball-killing in front of their posts. Walder reduced the deficit to one point with a 24th-minute penalty.
It was clear Wasps were struggling in the scrum. Another collapse and another penalty to touch saw Leicester back in the home team's half, where they had spent the majority of the opening half-hour.
And, when White spotted a maul being pulled down on his blindside, Flood's fourth successful penalty after 33 minutes arrowed home from wide out on the left.
Just when Leicester's followers were beginning to feel the reigning champions were comfortable, Flood sliced a clearance horribly. Geordan Murphy saved the day but only for a matter of seconds.
Mark Robinson's pass found Walder and his astute offload sent Kefu hurtling between the posts in the 35th minute. Walder converted, and added a penalty three minutes later as a stunned Leicester found themselves trailing at the break in a game they had largely dominated.
Wasps began the second half with increased intent, rewarded in the 49th minute by a Walder penalty after Leicester made consecutive mistakes under pressure.
And when Walder nailed his fourth penalty on the hour, only for Flood to reply in kind inside 60 seconds, the 10,116 crowd cranked up the atmosphere.
Flood then got the chance to close the gap further but hooked his 25-yarder and, with Wasps much steadier in the scrum now, they threatened to pull away.
But you cannot bet against the champions. Crane scored a last-minute try from a drive and Aaron Mauger nailed the conversion, but it only served to earn a losing bonus point.
Tries: Sackey, Kefu
Pens: Walder 4
Pens: Flood 5
Wasps:15 Mark Van Gisbergen, 14 Paul Sackey, 13 Dominic Waldouck, 12 Steve Kefu, 11 Tom Varndell, 10 Dave Walder, 9 Joe Simpson, 8 Dan Ward-Smith, 7 Serge Betsen (C), 6 John Hart, 5 Richard Birkett, 4 Simon Shaw, 3 Ben Broster, 2 Rob Webber, 1 Tim Payne.
Replacements: 16 Joe Ward, 17 Gabriel Bocca, 18 Bob Baker, 19 Dan Leo, 20 Will Matthews, 21 James Honeyben, 22 David Lemi, 23 Ben Jacobs.
Leicester: 15 Scott Hamilton, 14 Johne Murphy, 13 Anthony Allen, 12 Aaron Mauger (capt), 11 Lote Tuqiri, 10 Toby Flood, 9 Ben Youngs, 8 Jordan Crane, 7 Lewis Moody, 6 Brett Deacon, 5 Geoff Parling, 4 Louis Deacon, 3 Dan Cole, 2 Mefin Davies, 1 Marcos Ayerza.
Replacements: 16 George Chuter, 17 Boris Stankovich, 18 Robbie Harris, 19 Ben Kay, 20 Craig Newby, 21 James Grindal, 22 Jeremy Staunton, 23 Alesana Tuilagi.
Referee: Chris White