Sexton, who started each of Ireland's five RBS 6 Nations games, will look to help defending champions Leinster reach the Heineken Cup final with victory in France.
Leinster will cross the channel in high spirits after defeating Ulster last time out to sit top of the Celtic League - ten points clear of nearest challengers Ospreys.
But with star-studded Clermont also enjoying a fine domestic season - sitting second in the Top 14 tied on points with leaders Toulouse - Sexton has called on his team-mates to find another gear,
"We probably haven't played our best but we know this weekend we will have to be at our best and we'll have to do it for 80 minutes," he told the Irish Times.
"It's something we probably haven't done all season. We've had bursts where we've put teams away and then not had the ball but defended well.
"So we're going to have to be at our best with the ball and then any time they have it we'll have to be really switched on because they've got some fantastic players and strike runners and athletes, so it's going to be tough.
"Almost everyone in their squad is an international and a quality player, so no matter who they play or no matter who's injured they've got somebody really good to play and it is like playing Toulouse.
"They're probably the two teams in France that really go out and play, try and throw the ball around and play with a bit of tempo.
"A lot of the other teams, they slog it out and they try and bash each other, but these two have got some really good individual players and they try to play. In fairness to their coaches they give them licence to do that."