Saracens will reach the knock-out stages if they get a bonus-point win against Rovigo next week and Toulon fail to do the same against Castres.
"It would be some achievement to get out of this pool," Venter said.
Another player hoping to impress Johnson and nail down a place in the England team is Ugo Monye.
The Harlequins wing believes his side's seemingly hopeless trip to Toulouse in the Heineken Cup on Sunday could be a key part of his Six Nations Championship build-up along with fellow internationals Danny Care and Nick Easter. All three players are in the Quins side that have failed to make any impact in the Cup this season, having lost all four games.
"You want to test yourself against the best and we did well in our home pool game with Toulouse," said Monye, who is raring to go after recovering from a back spasm earlier this week.
"It's a preview for the Six Nations, with a number of the French players in their squad. It's going to be an intimidating atmosphere but we have to try to get back to winning ways."
Just like London Irish, who must win at Scarlets on Sunday to keep their Cup hopes alive, Quins will put out a strong side. Tom Guest is included on the flank, with England forward Chris Robshaw among the replacements.
Irish are still without wings Topsy Ojo and Sailosi Tagicakibau. Peter Hewat and Tom Homer have the wing roles against Scarlets, with the tough-tackling Samoan pair of Elvis Seveali'i and Seilala Mapusua back in harness at centre.
Richard Thorpe is joined on the flank by England No7 Steffon Armitage, while Ryan Lamb is preferred at outside-half to partner Paul Hodgson.
