Victory over Stade Francais moved Racing 92 to within four points of Top 14 leaders Montpellier but Toulon slipped to defeat at Oyonnax.
The leaders of the Top 14, Montpellier, thumped their nearest rivals on Saturday, while struggling Oyonnax also claimed an important win.
Defeat to Racing 92 would have seen Montpellier deposed as Top 14 leaders, but Vern Cotter's men made a statement with a bonus-point win.
Montpellier's lead at the summit was cut to three points after they went down at Agen and Racing 92 defeated struggling Brive.
Agen and Oyonnax secured rare wins at the foot of Top 14, while Montpellier enjoyed another successful day at the top.