Castres put Grenoble to the sword with a high-scoring 46-9 win on Sunday in the Top 14.
The home side were dominant from the outset of the match and didn't allow the visitors to ever really get into the game.
The win sees Castres jump up the table but unfortunately not high enough to overtake Toulouse who are just in front of them.
Grenoble stay at tenth spot after gaining no table points from the game.
Castres scrum-half Rory Kockott was the first to score for his side in the first ten minutes which set the tone for the rest of the game. Mathieu Babillot scored three minutes after him after a fantastic assist from former Cheetahs centre Robert Ebersohn.
It was all one way traffic as Jody Jenneker perpetuated the trend of South African scorers after the burly hooker barged over the line.
Afusipa Taumoepeau, Victor Moreaux, Marc-Antoine Rallier all crossed the white-wash throughout the game, with Thomas Combezou hammering their triumph home with a five-pointer in the 78th minute.
Tries: Kockott, Babillot, Jenneker, Taumoepeau, Moreaux, Rallier, Combezou
Cons: Urdapilleta 4
Pens: Bosch 3
Yellow Cards: Gelin, Oz
Castres: 15 Pierre Berard, 14 Horacio Agulla, 13 Afusipa Taumoepeau, 12 Robert Ebersohn, 11 David Smith, 10 Benjamin Urdapilleta, 9 Rory Kockott, 8 Alex Tulou, 7 Steve Mafi, 6 Mathieu Babillot, 5 Rodrigo Capo Ortega, 4 Loïc Jacquet, 3 Damien Tussac, 2 Jody Jenneker, 1 Mihaita Lazar
Replacements: 16 Marc-Antoine Rallier, 17 Antoine Tichit, 18 Victor Moreaux, 19 Alexandre Bias, 20 Antoine Dupont, 21 Julien Dumora, 22 Thomas Combezou, 23 Daniel Kotze
Grenoble: 15 Clément Gelin, 14 Edward Sawailau, 13 Chris Farrell, 12 Maritino Nemani, 11 Armand Batlle, 10 Gillies Bosch, 9 David Mélé, 8 Dylan Hayes, 7 Henry Vanderglas, 6 Peter Kimlin, 5 Thomas Jolmes, 4 Mathias Marie, 3 Roussouw de Klerk, 2 Laurent Bouchet, 1 Denis Coulson
Replacements: 16 Loïck Jammes, 17 Alexandre Dardet, 18 Jonathan Best, 19 Kevin Kornath, 20 Lilian Saseras, 21 Jéremy Valencot, 22 Bastien Guillemin, 23 Ali Oz
Referee: Adrien Descottes