Double Champions Cup winners La Rochelle are among a host of clubs battling for a place in the Champions Cup last 16 when they head to Sale in Pool 2 on Sunday in the final weekend of the group stage.
The French club, who have won the last two editions, have claimed just one victory this campaign, hammering Leicester 45-12 last Sunday.
Ronan O'Gara's outfit need just a draw in northern England to claim one of the eight spots remaining in the next round.
"It's a crucial week for the club and the squad," O'Gara told newspaper Midi Olympique after the win over Leicester.
"My challenge this week will be to give ourselves the chance to play the knockout stages, if we do a good job on Sunday.
"I will not accept being knocked out of this competition after a bad performance," the former Ireland fly-half added.
Fleet-footed winger Teddy Thomas scored twice in the Leicester victory but missed out on inclusion in France's Six Nations squad, named on Wednesday.
One La Rochelle player included in Les Bleus' set-up was No 8 Gregory Alldritt, who was named captain in Antoine Dupont's absence.
"He's got X-factor," O'Gara said of Thomas.
"When the ball falls, you give it to him and it's goodbye.
"Few players are capable of doing that in the world," he added.
The five other Six Nations squads were also named this week with the tournament starting on February 2, leaving head coaches watching on wearily with a host of front-line players such as Ireland winger Mack Hansen, England centre Manu Tuilagi and Wales captain Jac Morgan having already been ruled out through injury.
Elsewhere this weekend, former champions Saracens, Ulster, Munster, Leicester and Toulon are also among the sides eyeing spots in the last 16.
Three-time winners Toulon head to Glasgow in Pool 1 on Friday, needing to claim their first win of the season in the tournament and for Bayonne to fail to beat Exeter on Sunday, with the competition's new format still suffering from teething issues.
"It's normal when you lose three games, your destiny is out of your hands," Toulon head coach Pierre Mignoni told reporters this week.
"The players know we're not where we want to be, but we know we're not far off," he added.
Other stand-out ties this weekend include a re-run of the 2000 final as Munster host Northampton and Leicester welcome Leinster in a repeat of 2009's decider.
Siya Kolisi's Racing 92, three-time runners-up, need a victory over a youthful Cardiff to keep alive their slim hopes of a spot in the last 16.
Fixtures (all times GMT)
Friday
Pool 1: Connacht (IRL) v Bristol (ENG); Pool 3: Glasgow (SCO) v Toulon (FRA) (both 2000)
Saturday
Pool 1: Bulls (RSA) v Bordeaux-Begles (FRA) (1300), Saracens (ENG) v Lyon (FRA) (2000)
Pool 2: Harlequins (ENG) v Ulster (IRL) (1300), Racing 92 v Cardiff (WAL) (1515)
Pool 3: Munster (IRL) v Northampton (ENG) (1730)
Pool 4: Leicester (RSA) v Leinster (IRL) (1515), Stade Francais (FRA) v Stormers (RSA) (1730)
Sunday
Pool 2: Sale (ENG) v La Rochelle (FRA) (1300)
Pool 3: Toulouse (FRA) v Bath (ENG) (1515)
Pool 4: Bayonne (FRA) v Exeter (ENG) (1730)
