Clermont boss Franck Azema knows that his side's victory over UBB on Friday will mean nothing if they don't win against the Ospreys.
The victory means that Clermont now top Pool 2 in the Champions Cup by two points ahead of the Welsh region.
The two sides meet next Friday at the Liberty Stadium as the hunt for top spot heats up.
"It was a tough game and it was very important for us to win it. We knew it was going to be a head-on match and we are pleased with the victory," Azema told the EPC Rugby website.
"My only regret is that in the final 15 minutes we didn't aim for the bonus point try. But four points in Bordeaux is a good performance.
"We know we've got another hard game against the Ospreys next week and if we don't win that one it means this result will have been for nothing."