Wasps’ victory ruined Ulster’s hopes of progressing to the quarter-finals but their win paved the way for their fierce rivals, Saracens, to survive as the only remaining English club.
Wasps’ win took them above Ulster to finish as runners-up in Pool One but their 17-point tally was insufficient for them to qualify and they can only reflect on their poor performances at Harlequins and Ulster, which ultimately proved costly.
Tom Cruse, Guy Thompson, Jake Cooper-Woolley and Willie Le Roux scored Wasps’ tries with Danny Cipriani converting three.
Sean Reidy scored a try for Ulster, which John Cooney converted.
Wasps declined a couple of early kickable penalties in favour of attacking line-outs and were rewarded with an 11th-minute try from Thompson when Ulster could not stop a forward drive.
Cipriani converted before the Irish side suffered a further setback when their national squad wing Jacob Stockdale limped off and was replaced by Rob Lyttle.
Both sides tried to play some open rugby but the miserable conditions made it virtually impossible and hence Thompson’s converted try was the only score of the opening quarter.
Against the run of play, Ulster drew level when Christian Wade tried to run out of defence but his pass was intercepted by Louis Ludik and the visitors capitalised with Darren Cave sending Reidy over.
After 31 minutes, Wasps regained the lead with a splendid try which belied the conditions. They produced a flowing move, which ended with Cruse collecting a superbly judged kick from Cipriani to score. Cipriani then knocked over the conversion from the touchline to give his side a deserved 14-7 lead at the interval.
At half-time, Ulster lost another wing through injury when Ludik was unable to reappear, having failed a head injury assessment.
After the restart the home side continued their ascendancy and were rewarded with their third try.
An elusive run from Le Roux put the Ulster defence on the back foot and when Wasps nicked a turnover, a well-judged long pass from Cipriani sent Le Roux haring for the line.
The home side sealed victory in the 55th minute when Cooper-Woolley forced his way over from close range for the bonus-point try.
With the game won, Wasps emptied their bench with Cooper-Woolley one of the players to leave with Joe Simpson replacing Dan Robson at scrum-half as the game fizzled out in the final quarter.
Tries: Thompson, Cruse, le Roux, Cooper-Woolley. Cons: Cipriani 3.
Tries: Reidy. Cons: Cooney.
Le Roux, Wade, de Jongh, Eastmond, Watson, Cipriani, Robson, McIntyre, Cruse, Cooper-Woolley, Launchbury, Gaskell, J. Willis, Thompson, Carr.
Macken for Eastmond (67), Simpson for Robson (62), B. Harris for McIntyre (62), Johnson for Cruse (63), Moore for Cooper-Woolley (62), Myall for Gaskell (55), Young for J. Willis (55).
Piutau, Ludik, Cave, McCloskey, Stockdale, Lealiifano, Cooney, McCall, Best, Ah You, O’Connor, Treadwell, Henderson, Reidy, Timoney.
Shanahan for Cooney (73), Warwick for McCall (55), Herring for Best (58), Herbst for Ah You (51), Rea for Treadwell (58), Henry for Timoney (66).