The match was tied at two penalty kicks apiece courtesy of Racing's Jonathan Wisniewski and Clermont's Brock James with less than 20 minutes remaining, but the visitors then lost prop Raphael Chume to the sin-bin and tired legs fell prey to late pressure from the home side.
Wisniewski kicked another two penalties to seal the victory which leaves Racing seventh in the table with four points on Perpignan, who bested Clermont last time out.
Clermont remain second, but are six points behind league leaders Toulon who have a game in hand, as do third-placed Toulouse who can overtake them with victory at Agen on Saturday.
