Harlequins director of rugby Conor O'Shea confirmed he is taking the Amlin Challenge Cup seriously after naming a strong team for Friday's quarter-final against Stade Francais in Paris.
England players Mike Brown, Danny Care, Chris Robshaw and Joe Marler, who makes his 100th appearance for the club, are in the starting XV at the Stade Jean-Bouin.
Quins are sixth in the Aviva Premiership table, six points off a play-off place, and the Challenge Cup is arguably their best chance of claiming silverware this season.
"This is a competition that means a lot to us. We won it three seasons ago. Leinster won it last year and it's a really hard competition," said O'Shea.
"We fought hard in the Heineken Cup, beating Racing Metro home and away, playing Clermont and winning at the Scarlets to get into the Amlin. We're not going to do all that hard work and chuck it away.
"It's a huge task playing Stade, enormous. Stade lost at home last weekend for the first time this season so they'll be smarting from that.
"We're going full-bore for every game now. This is the run in now, so it's all hands to the pump."
O'Shea has made just two changes to the starting line-up from the side that defeated London Irish on Saturday, with Tim Molenaar getting the nod at outside centre and Charlie Matthews at lock.
Stade Francais have made a 12 changes to the side that narrowly lost the Paris derby last weekend as they line-up a makeshift team.
Springbok fly-half Mornr Steyn does retain his starting berth but there is no sign of the French team's Six Nations contingent as they look to save their key personnel for the Top 14 season run-in.
The Stade Francais game is a repeat of the 2011 final which Quins won 19-18, with the Londoners buoyed by the knowledge they have won at Racing, Biarritz and Toulouse in the last three seasons.
Stade Francais: 15 Lydon, 14 Kingi, 13 Williams, 12 Danty, 11 Camara, 10 Steyn, 9 Daguin; 1 Zhvania, 2 Sempere (c), 3 Kubriashvili, 4 Mostert, 5 Wegner, 6 Garrault, 7 Missoup, 8 Lyons.
Replacements:16 Van Vuuren, 17 Frou, 18 Slimani, 19 Van Zyl, 20 Rabadan, 21 Mallet, 22 Cocagi, 23 Arias
Harlequins: 15 Brown, 14 Lindsay-Hague, 13 Molenaar, 12 Turner-Hall, 11 Smith, 10 Evans, 9 Care; 1 Marler, 2 Ward, 3 Sinckler, 4 Matthews, 5 Robson, 6 Wallace, 7 Robshaw (C), 8 Easter.
Replacements: 16 Buchanan, 17 Lambert, 18 Doran Jones, 19 Merrick, 20 Guest, 21 Dickson, 22 Botica, 23 Sackey.
Watch Stade Francais v Harlequins on Sky Sports 2 from 7pm on Friday.