Now Dallaglio believes the French hooker is the man who can make the French forwards tick as a collective unit and that is what stands between England and the World Cup final.
Dallaglio said: "He has vast experience. He knows the game. He's been there and done it in World Cups. He's had great victories and great disappointments. He'll be able to put this match into perspective.
"He's a great character. He captained France in 1999 and he's still there eight years later, that says it all really. International rugby is not somewhere you hang around if you are not a strong character.
"I was very keen we signed him at Wasps and his arrival has been a huge part of our success."
Dallaglio, who came off the bench for the last 10 minutes against Australia, cannot wait to be part of what is sure to be a frantic atmosphere this weekend at the Stade de France.
But he knows that, despite the brilliant England performance against the Aussies, Brian Ashton's men will need to ratchet up the intensity even more against the host nation.
He said: "It's a huge carrot. For France the chance to be in a World Cup final in their own country and for England the chance to be in back-to-back World Cup finals.
"A France v England semi-final is not what a lot of people would have expected but we're here and both teams thoroughly deserved their plaudits.
"There was much to be excited about against Australia but when we looked at the performance in the cold light there was much room for improvement.
"It was a huge step-up but another one is required this weekend.
"We're both in the semi-finals because we deserve to be there with performances which form would not have suggested coming into this game. In this game the form book goes out of the window."