Clermont skipper Aurélien Rougerie has pinpointed former team-mate Pierre Mignoni as the man to be wary of in Saturday's Top 14 semi-final against Toulon.
Toulon will include Clermont old boys Mignoni and Laurent Emmanuelli in their line-up on Saturday, while England fly-half Jonny Wilkinson has been in imperious form for the big-spenders.
However Rougerie believes Mignoni, who spent six seasons at Clermont before he headed back to Toulon last year, and his inside knowledge of Les Jaunards could be the difference.
"Toulon is a very complete team with great individuals including Wilkinson obviously," said Rougerie.
"Above all they've got the advantage of having players who know us very well like Mignoni and Emmanuelli.
"It's a great advantage to have all that knowledge and to know how Vern (Cotter, Clermont coach) works, how the group works, the tactics that we could use.
"But that is not going to force us to change anything. He (Mignoni) knows the combinations but he can't guess which ones we are going to use."