After last Saturday's agonising defeat to Leicester, Harlequins turn their attention back to the Amlin Challenge Cup when they take on rivals Wasps.
A win would see Quins into the semi-final and one step closer to that elusive silverware which includes a guaranteed place in next season's Heineken Cup.
Wasps fell just short in the group stages of the Heineken Cup, finishing second in Pool 6 to reigning European champions Toulouse, but their form in domestic competition has been particularly disappointing this term.
Defeat to London Irish last weekend was Wasps' ninth in their last 11 fixtures in all competitions. Losing has become a worrying trend for a side who for so long seemed to find a winning way whenever it really mattered.
For a team who have been crowned English champs four times in the last eight years, to be currently sitting seventh in the Aviva Premiership, some 13 points adrift of a play-off spot, isn't deemed good enough.
In team news, there are two changes to the Harlequins side that started against Tigers last week; both in the forwards.
Ceri Jones (replacing Joe Marler), John Andress and Joe Gray link together in the front row, with Ollie Kohn and George Robson continuing their second row partnership.
Maurie Fa'asavalu, Will Skinner and Nick Easter make up the back row. Chris Robshaw, who recieved a deep cut to the knee against Tigers, will only be absent for one match, with Nick Easter covering as captain.
Last week's try-scorer, Danny Care, will look to continue his half-back pairing with Nick Evans, with Jordan Turner-Hall and George Lowe starting in the centres.
Ugo Monye and Gonzalo Camacho retain their positions on the wings, with Mike Brown at full-back. James Johnston, Chris Brooker and Pete Browne come onto the bench.
Meanwhile, London Wasps have made four changes to their starting line-up. There are two changes in the backs and two in the pack.
Richard Haughton returns on the wing, having recovered from injury. Centre Ben Jacobs is also back from injury and he fills the outside centre berth in the place of Dominic Waldouck who suffered an Achilles injury in the game against London Irish.
Waldouck will have surgery this Friday and will be out for six months.
Up front Ben Broster returns at prop with Zak Taulafo moving to the bench while there is also a first ever European start for young second-row Joe Launchbury, who has caught the eye this year as a real future star in the making for the club.
John Hart retains the captaincy.
"It's no secret that we've been hit by injuries in recent weeks but I am pleased to be able to name such a strong team for what is now a vital match for us," said London Wasps interim Director of Rugby Leon Holden.
"Playing Harlequins is always a huge game for the team and our fans and we're going into this on the back of a good week at the training ground.
"The players are really up for it and we're hoping we can pull out a big performance and what would be a massive win."
Harlequins: 15 Mike Brown, 14 Gonzalo Camacho, 13 George Lowe, 12 Jordan Turner-Hall, 11 Ugo Monye, 10 Nick Evans, 9 Danny Care, 8 Nick Easter (c), 7 Will Skinner, 6 Maurie Fa'asavalu, 5 George Robson, 4 Ollie Kohn, 3 John Andress, 2 Joe Gray, 1 Ceri Jones.
Replacements: 16 Chris Brooker, 17 Mark Lambert, 18 James Johnston, 19 Pete Browne, 20 Tomas Vallejos, 21 Dave Moore, 22 Rory Clegg, 23 Tom Williams.
London Wasps: 15 Mark van Gisbergen, 14 Richard Haughton, 13 Ben Jacobs, 12 Riki Flutey, 11 David Lemi, 10 Dave Walder, 9 Joe Simpson, 8 Andy Powell, 7 Dan Ward Smith, 6 John Hart (c), 5 Joe Launchbury, 4 Simon Shaw, 3 Ben Broster, 2 Rob Webber, 1 Tim Payne.
Replacements: 16 Tom Lindsay, 17 Charlie Beech, 18 Zak Taulafo, 19 James Cannon, 20 Serge Betsen, 21 Nic Berry, 22 Christian Wade, 23 Seb Jewell.
Date: Friday, April 8
Venue: Twickenham Stoop
Kick-off: 19:45 GMT
Referee: Christophe Berdos (France)
Assistant referees: Pascal GauzÃ¨re (France), Jean-Luc Rebollal (France)
Television match official: Giulio De Santis (Italy)