Christian Wade scored a try in each half as Wasps sealed a Premiership play-off spot with a 36-29 defeat of spirited Northampton Saints, and Saracens hammered relegated London Irish to seal a home semi-final.
There were reports of a player mutiny at Wasps this week, but Dai Young's men put on a united front to secure a victory which guaranteed them a top-four finish with one game of the regular season to spare and leaves Leicester Tigers' chances hanging by a thread.
Last year's runners-up are up to third and lead fourth-placed Newcastle Falcons - who they play at Kingston Park next weekend - by three points after scoring four tries in an entertaining contest at the Ricoh Arena, where Northampton pushed them all the way.
Clinical wing Wade scampered over to put Wasps in front and Elliot Daly finished off a fluent move either side of five pointers from Teimana Harrison and Api Ratuniyarawa at the other end.
Eleven points from the boot of Jimmy Gopperth and seven for Stephen Myler made it 21-17 to Wasps at the break, but Wade was on hand to finish in the corner for a second time and a Juan de Jongh try gave the home side breathing space.
Northampton were not finished yet, Alex Mitchell and Ahsee Tuala crossing in quick succession, but Gopperth added another penalty as Wasps held on to book a place in the last four.
Sarries will finish second behind Exeter Chiefs after rubbing salt into London Irish's wounds with a brutal 51-14 seven-try thumping at the Madejski Stadium.
Worcester Warriors secured their top-flight status on Saturday to send the Exiles straight back down and Sarries showed no mercy to the Championship-bound side, Brad Barritt and Alex Goode among the try-scorers and Owen Farrell scoring 16 points from the tee.