Castres moved into the Top 14 play-off places with a 33-28 victory over Grenoble at the Stade des Alpes on Friday.
Benjamin Urdapilleta's 100 per cent kicking record across three conversions and four penalties helped Castres secure an away win against a Grenoble side seemingly suffering in the aftermath of a hard-fought Challenge Cup win over Connacht.
Castres took a 17-9 lead into the break thanks to tries from Thomas Combezou and Alex Tulou, with Jonathan Wisniewski completing a trio of successful penalties after Rossouw de Klerk and Antoine Tichit were shown yellow cards seven minutes before half-time.
Two further Wisniewski penalties brought the hosts to within two points, and he continued to trade kicks with Urdapilleta.
But Castres opened up a 12-point lead inside the final 10 minutes when David Smith crossed, putting the victory beyond doubt.
The visitors saw Yannick Caballero shown a yellow card for catching Mahamadou Diaby high in the 76th minute and Grenoble took advantage with Maritino Nemani's try converted for a bonus point.