Toulon, who are two points ahead of their nearest rivals the Newcastle Falcons, know they are in the driving seat and will be expected to beat the Italian part-timers and to qualify from the Pool.
Toulon also know a draw against the Italian minnows will be enough to make the last eight of the tournament if the Newcastle Falcons don't get a bonus point victory in their 'must win' clash in Lyon.
Petrarca rugby are still looking for their first points, let alone victory, of the Pool and face a stern test against a Toulon side which recorded a 53-22 win against them in the opening game of the campaign.
Lyon Rugby v Newcastle Falcons
(Saturday January 21, KO 15:00)
Newcaslte Falcons have it all to do when they travel to face European rugby's new boys, Lyon, if they are to qualify for this season's Amlin Challenge Cup quarter-finals.
The Premiership side are two points behind Pool leaders, Toulon, and need to get a bonus point victory over a Lyon side, who are in their first season of European rugby, at the Malmut Stadium.
The Falcons have won as many games as leaders Toulon, but have been outscored by the French side who have scored four bonus points in four of their five games during this campaign.
Lyon, who lost the first game between the sides 27-19 at Kingston Park, have won two of their Pool games but having nothing to play for but pride when they host the Falcons.