Northampton Saints boss Jim Mallinder has said victory over Ospreys on Sunday is essential if they are to progress past the Heineken Cup pool stage.
Saints started their European campaign with in France on Saturday.
"We have to have a massive week. Come Sunday we need to win at home," director of rugby Mallinder told BBC Radio Northampton.
"In the Heineken Cup you can't afford to lose your home games."
In Pool One's other fixture, Leinster to go top of the group.
It means the region will be pointless when they visit Franklin's Gardens this weekend.
"It's six games and that's what you've got to look at," added Mallinder.
"We've had our first game away to the French champions.
"We haven't won, but we came close and got the point. So we're still certainly well in the tournament.
"Clearly Ospreys have got a good side - the front five in particular.
"It's a massive challenge for us but if you want to be successful in the pool stages you have got to win your home games."