Nick Evans is sweating on being fit to spearhead Harlequins' Amlin Challenge Cup quarterfinal bid against Toulon at Stade Felix Mayol on Friday.

However, the prospect of a head-to-head contest with Jonny Wilkinson is giving the former All Blacks flyhalf added incentive to be declared fit for the defending champions' French test.

Evans injured an ankle in his club's 24-19 victory over Saracens at Wembley on Saturday and explained: "It might be a bit touch and go at the moment. I tweaked something in my ankle and it is a bit sore but I really want to play against Toulon.

"It would be massive to play against a legend like Jonny and that chance gives me an added incentive to be fit as I have never had a 10 on 10 match-up with him.

"A lot depends on who they pick at 10 as Jonny is a great attacking player who also plays a big territorial game while Matt Giteau is perhaps more of an attacking threat.

"However, they have got a big pack and it could be a long day at the office for our forwards."

Evans kicked the 78th minute touchline conversion in the 2011 Challenge Cup Final against Stade Francais Paris that clinched a record third tournament triumph for Harlequins and insists they will mount a fierce defence of their crown.

"Winning the Challenge Cup last year was huge for us as it showed we could compete at the highest levels of European club rugby," he said.

"We are the champions and, while Toulon is a tough place to play and an even tougher place to win, we will not go down without a fight.

"We were disappointed about not qualifying for the Heineken Cup quarters as we could not quite cross the line but we are still in Europe and we have a massive game ahead of us on Friday night."

Wilkinson played the full 80 minutes in Toulon's Top 14 Round 22 defeat at Brive, kicking all their points with three penalties in the 14-9 reverse, and they remain healthily placed in third position for automatic Heineken Cup qualification next season.

"I have never played in Toulon but I have heard how immense the crowd factor is - and what a special atmosphere that creates," added Evans.

"Toulon have so many quality players on their roster that you can never be quite sure who they will play but whatever side they put out it will be extremely strong and packed with international players from all over the world."

Three Harlequins players were yellow carded in the Wembley win, along with a flood of penalties against them, and Director of Rugby Conor O'Shea accepted that any repeat could be disastrous.

"Our discipline let us down, some very dumb penalties, and we need to address that ahead of the Amlin quarterfinal," he said.

"But our defence was outstanding, they put their bodies on the line, and the team that plays against Toulon will have to follow that lead."

All the fixtures and teams for the quarterfinals!

Thursday, April 5:

Stade Francais v Exeter Chiefs
(Stade Charléty - Kick-off: 20.45; 18.45)

Teams:

Stade Français: 15 Djibril Camara, 14 Paul Sackey, 13 Morgan Turinui, 12 Paul Williams, 11 Julien Arias, 10 Felipe Contepomi, 9 Julien Dupuy, 8 Sergio Parisse, 7 Antoine Burban, 6 George Smith, 5 Pascal Pape, 4 Anton van Zyl, 3 Rabah Slimani, 2 Dimitri Szarzewski, 1 Rodrigo Roncero.
Replacements: 16 Laurent Sempere, 17 Olivier Milloud, 18 Stan Wright, 19 Alexandre Flanquart, 20 David Lyons, 21 Pierre Rabadan, 22 Jerome Fillol, 23 Hugo Bonneval.

Exeter Chiefs: 15 Phil Dollman, 14 Gonzalo Camacho, 13 Bryan Rennie, 12 Jason Shoemark, 11 Matt Jess, 10 Ignacio Mieres, 9 Haydn Thomas, 8 Richard Baxter, 7 James Scaysbrook, 6 Tom Johnson, 5 James Hanks, 4 Tom Hayes (captain), 3 Craig Mitchell, 2 Chris Whitehead, 1 Hoani Tui.
Replacements: 16 Neil Clark, 17 Ben Moon, 18 Chris Budgen, 19 Aly Muldowney, 20 Ben White, 21 Kevin Barrett, 22 Gareth Steenson, 23 Sireli Naqelevuki.

Referee: Peter Fitzgibbon (Ireland)
Assistant referees: James Jones (Wales), David Wilkinson (Ireland)
TMO: Jim Yuille (Scotland)

Friday, April 6:

Toulon v Harlequins
(Stade Félix Mayol - Kick-off: 20.45; 18.45)

Teams:

Toulon : TBC

Harlequins: TBC

Referee: George Clancy (Ireland)
Assistant referees: Dudley Phillips (Ireland), Carlo Damasco (Italy)
TMO: Marshall Kilgore (Ireland)

Saturday, April 7:

London Wasps v Biarritz Olympique
(Adams Park - Kick-off: 12.30; 12.30 GMT)

Teams:

London Wasps: TBC

Biarritz Olympique: TBC

Referee: John Lacey (Ireland)
Assistant referees: Peter Allan (Scotland), Leo Colgan (Ireland)

Sunday, April 8:

Brive v Scarlets
(Stadium Municipal - Kick-off: 20.15; 18.15 GMT)

Teams:

Brive: TBC

Scarlets: TBC

Referee: Wayne Barnes (England)
Assistant referees: Greg Garner (England), Paul Dix (England)
TMO: Graham Hughes