Dai Young accepts that "a number of things" have to work in Wasps' favour if their European Champions Cup campaign is to progress beyond the pool stage.
Even a bonus-point victory over Ricoh Arena visitors Ulster on Sunday is unlikely to be enough in the pursuit of a quarter-final place.
Wasps' capitulation against Harlequins last weekend, when they blew a 21-point lead and lost 33-28, pushed them halfway through the exit door.
Young's men look set to finish third in Pool One, with French challengers La Rochelle - they have home advantage against already-eliminated Quins on Sunday - favourites to win the group.
"Plenty always goes on during the final weekend of the European Cup pool stages," Wasps rugby director Young said.
"But we have to concentrate on our game with Ulster, pure and simple.
"We have plenty to put right from the last few weeks, and have been working hard on those things in training.
"We can only control events at the Ricoh. A number of things must happen for us to have any chance of reaching the quarter-finals, but it all starts with us beating Ulster."
South Africa international centre Juan De Jongh returns after injury for Wasps, partnering Kyle Eastmond in midfield, while former England Under-20 flanker Jack Willis takes over from a suspended James Haskell.
Leicester's miserable European campaign will draw to a close against French opponents Racing 92 at Welford Road on Sunday.
The Tigers, European champions in 2001 and 2002, prop up Pool Four, six points behind third-placed Castres, with Munster and Racing fighting it out for top spot and automatic last-eight qualification.
A bonus-point win for Munster over Castres in Limerick on Sunday would guarantee they win the pool, but a Racing victory against Leicester could see them progress as a best runner-up even if Munster triumph.
Leicester head coach Matt O'Connor said: "We have obviously not done as well as we would have liked in Europe this season.
"But this is a huge opportunity to put in a big performance against one of the premier teams in the tournament in front of our own fans at Welford Road.
"Racing have a lot of world-class players in the group, they are chasing a place in the quarter-finals, and we need to put out a big performance against a team of that quality."
O'Connor fields a far stronger side than the one he took to Castres last weekend - Tigers lost 39-0 - with England quartet George Ford, Ben Youngs, Jonny May and Dan Cole all starting. Prop Cole makes his 50th European Cup appearance.