Lyon and Toulouse were both winners in Sunday's Top 14 action, with Patricio Fernandez impressing for the former.
Bordeaux-Begles, nudged into second on Saturday, could not return to the Top 14 summit at Toulouse.
Rhys Carre's early red card made life difficult for Saracens, but they still defeated Ospreys in the European Champions Cup.
Stade Francais came into the Clasico sitting bottom of the Top 14, yet they pulled off a thrilling win in Paris as Toulouse wilted.
Bordeaux-Begles are back at the top of the Top 14 and increased their advantage over Toulon and Toulouse.
Handre Pollard missed some crucial kicks on his Montpellier debut while Top 14 leaders Lyon
Rob Baxter's Exeter Chiefs survived a late scare to defeat Sale Sharks and remain firmly on track for the Champions Cup quarter-finals.
Toulouse have hit form and made light work of Bayonne at home, while Brive defeated Stade Francais.
Ospreys were no match for Saracens on Saturday, while Exeter Chiefs were among the other European Champions Cup winners.
Scrum-half Joe Simpson scored two first-half tries but Gloucester could not contain Toulouse after the break at Kingsholm.