"I have never played a game in France that wasn't hugely demanding, and this one will be right up there with internationals in terms of speed, intensity and physicality," says O'Callaghan who started the second and third Tests for the Lions in New Zealand.
"But you wouldn't have it any other way and we're certainly aiming to give it our best shot.
"Clermont will be looking to put one over on us for last season, when we effectively stopped them making the knockout stages. If anything, that defeat will probably make them even more determined."
Munster's task is made even more demanding by the absence of a number of key players, with the likes of Irish internationals and Lions contenders Jerry Flannery and Denis Leamy and New Zealand Maori centre Rua Tipoki unavailable for the trip to the Stade Marcel Michelin.
Munster skipper O'Connell admits that injury issues have been a disappointing blow but the 29-year-old believes his side still have what it takes to leave France with a famous victory.
"No side in this competition or anywhere could be happy losing the likes of Rua, Denis Hurley, Jerry or Leamy on an individual basis never mind at the same time," said O'Connell, who was an ever present in the Lions Test XV last time around and has been mentioned as a possible captain for the tour to South Africa next summer.
"But we have 30 odd players hungry to be in the starting XV and that can only be a good thing. I think that's an indicator that our squad is stronger now than it has been in the past."
Munster currently sit second in Pool 1 with two wins from two games, just two points behind English side Sale Sharks who have played a game more.