PARIS — Double defending champions Leinster face the daunting task of travelling to Clermont in the European Cup this weekend in the first of a mouthwatering double-header between two of the continent’s rugby heavyweights.

The Irish province and French giants are both unbeaten in Pool 5, but Clermont have a two-point advantage thanks to two crucial bonus points from games against Scarlets and Exeter.

The matches throw up the chance for Leinster’s Kiwi coach, Joe Schmidt, to return to Clermont, where he worked under compatriot Vern Cotter before relocating to Ireland. He is now being touted as a likely candidate for the coaching team for the British and Irish Lions to Australia next summer.

"Qualifying from the pool will depend on this double header," said Cotter. "They, as we have done, have long marked this date in the calendar.

"My players are very excited, focused and motivated by the idea of playing this match."

Cotter said Leinster, who beat Clermont 19-15 in last season’s semifinal, were not a team to be underestimated come Sunday.

"They’re a team which control the ball well and play with a lot of speed. They’re used to big matches and this competition.

"With a two-point deficit on us, they know they don’t have any other solution than to go away with a result here. I know Joe well and I’m sure he’ll try to move the ball around. We’ll have to be ready to adapt by remaining focused and accurate."

Leinster prop Cian Healy added: "We’re pretty focused on Clermont and what we have to do there. It’s a big two games and what we have to bring to that away game is going to be a big ask.

"We expect the exact same again. Their physicality is a big thing they bring and their defence is hard," Healy said.

Clermont are just one of three heavy French hitters in action this weekend. Four-time European champions Toulouse are in action against Ospreys, and Toulon travel to struggling English club Sale on Saturday.

Toulouse have lost just eight of their previous European Cup encounters at home and the injury-hit Ospreys are likely to suffer against the French side, who will probably still be missing France captain and flanker Thierry Dusautoir.

But Toulouse will be boosted by their 30-22 victory over Clermont in the Top 14 last weekend and know they cannot rest on their laurels with Leicester also in their Pool 2.

The star-studded Toulon side romped past Grenoble 39-3 in the domestic league to head to the north of England bristling with optimism. Unbeaten English sides Harlequins and Saracens face away trips to Italian outfit Zebre and Munster respectively this weekend.