Former Sharks scrumhalf Charl McLeod scored a second-minute try for Grenoble in their 30-12 win against La Rochelle in the French Top 14 this weekend.
Grenoble scored three tries in all, while the visitors could only manage three penalties.
Meanwhile, former Stormers hooker Deon Fourie scored one of two late tries for Lyon, who beat Oyonnax 26-23.
In other notable results, Stade Français overcame a second-half slump to down Bayonne 34-29 to get their Top 14 campaign back on track, Clermont thrashed Racing Métro 32-6, while Frédéric Michalak kicked six penalties as champions Toulon laboured to an 18-13 win over Bordeaux-Bègles.
Round 4 results:
Montpellier 43 Castres 10
Brive 26 Toulouse 19
Clermont 32 Racing Métro 6
Grenoble 30 La Rochelle 12
Lyon 26 Oyonnax 23
Stade Français 34 Bayonne 29
Toulon 18 Bordeaux-Bègles 13
Photo: Jean-Pierre Clatot/AFP Photo