But at Pierre Antoine it was Castres who proved much the stronger outfit, thanks in particular to scrum-half Rory Kockott as they emerged comfortable victors.
And the double Grand Slam-winning centre admits his team need to react quickly to get themselves back on track.
He said: "It's a big disappointment because we played well in the first half but were poor after the break.
"We have to bounce back now. We had won four games in a row, now we have to add on a defeat. It's not a catastrophe but we will have to show solidarity to recover from this.
"We will go to Racing Metro next and they are full of confidence. They will be waiting for us so we will see whether we have the resources to take on a direct rival for the play-offs.
"We need to concentrate ourselves again and go back to what made us strong in the early weeks of the season."