Castres boosted their hopes of a place in the end of season play-offs with a grinding 12-0 win at home to Clermont in the French Top 14 on Saturday.
In filthy conditions with driving rain, Castres, who have yet to lose at home this season, were unable to cross the paint, but four penalties from Argentinian fly-half Benjamin Urdapilleta - two in each half - were enough to secure the victory.
"We played the game we needed given the weather conditions," said Urdapilleta.
"We played well tactically. We have an intelligent group, we know how to play this kind of match."
The key moment came at the end of the first half when Clermont were camped in Castres territory and seemed certain to score.
"When I saw how our forwards defended, I wanted to cry," said Urdapilleta.
"To see their commitment, how they managed to hold on... when you see that, it makes you want to fight."
It takes Castres, for the moment, into third place, four points ahead of La Rochelle who host Perpignan later Saturday, and one point behind Bordeaux-Begles who face leaders Montpellier on Sunday.
The top two advance directly into the semi-finals with the teams finishing third to sixth going into the first round of play-offs.
Defeat leaves Clermont eighth, the minimum for entry into next season's European Champions Cup.
Stade Francais, down in 11th, improved their hopes of a top eight finish with a 21-18 win at home against Pau.
After tries from Adrien Lepegue, Lester Etien, Pierre-Henri Azagoh, the Parisians led 18-6 and were on course for an offensive bonus but Pau hit back with two late tries from fly-half Antoine Hastoy to level at 18-18.
A late penalty from Nicolas Sanchez clinched the win for Stade who moved one point behind Pau who collected a bonus point, and four behind eighth-placed Clermont.
Ninth-placed Toulon will be without injured South African star Cheslin Kolbe as they attempt to push for a place in the play-offs when they host Toulouse in Saturday's late game.