Richard Baxter will achieve what he describes as "the pinnacle of my career" when Exeter make their Heineken Cup debut against Leinster (kick-off 3.40pm).

The Chiefs could hardly face a tougher tournament baptism – the holders away from home - but number eight Baxter believes it is a challenge Exeter must embrace.

"Isn't this what you want to be doing, playing for a successful club and in big games throughout the year?" he said.

"To play in the Heineken Cup will be the pinnacle of my career, and to play in games like these is fantastic."

Leinster, bidding for a European title hat-trick this term, and French challengers Clermont Auvergne are expected to take the top two spots in Pool Five - only the winners are guaranteed qualification - but Exeter and Welsh challengers the Scarlets cannot be written off.

Exeter warmed up for Europe by scoring more than 40 points against Aviva Premiership champions Harlequins last weekend, and Baxter added: "That was right up there among my greatest wins in an Exeter shirt.

"We had a bunch of guys out there who put in a massive effort and work-rate and did their jobs really well.

"The more you progress as a club, the more you have to use your squad to its full potential" - Richard Baxter

"The more you progress as a club, the more you have to use your squad to its full potential, and that game showed we have got guys who can step in and do a very good job."

O'Connell returns

Former Bath fly-half Olly Barkley is set to start for Racing at Stade de France, while Munster welcome back Ireland and Lions lock Paul O'Connell from injury for his first appearance in more than five months.

"We've always maintained that Paul would be back when he felt he was ready. I think it's great for us," Munster coach Rob Penney said.

"It is great for Irish rugby, for the rugby community, to see a player of his calibre back playing again. It was a gradual process, but, in the interests of the player, it had to be."

Premiership newcomers London Welsh, meanwhile, make their debut in the second-tier Amlin Challenge Cup with an attractive home fixture against twice Heineken finalists Stade Francais.

Wasps are also at home, entertaining Newport Gwent Dragons, but three English contenders - Bath, Worcester and London Irish - face trips to Bucharest, Gernika in Spain and Bordeaux, respectively.