Paris (AFP) - Argentina fly-half Benjamin Urdapilleta slotted 14 points as Castres beat French Top 14 leaders Toulouse 27-17.
The hosts moved seven points clear of the relegation play off spot with just their third win since December also thanks to Julien Dumora's double
The record 21-time champions remain top after losing for just a third time this calender year as the Top 14 returned after a two-week break following the end of the Six Nations
Toulouse chose to rest France Six Nations squad members including Antoine Dupont and Romain Ntamack before next weekend's Champions Cup last 16 tie with the Bulls.
Urdapilleta, who turned 37 earlier this month, took his side, coached by ex-Ireland lock Jeremy Davidson, to a 6-0 lead after 20 minutes with two penalty goals.
Full-back Melvyn Jaminet, who was an unsued substitute during Les Bleus' win over Wales last Saturday, halved the lead before five-time champions Castres took control of the tie.
Dumora kicked a penalty with Urdapilleta off due to a yellow card before Jaminet's counterpart Dumora crossed with a minute left of the half.
Urdapilleta, who scored a league record 33 points in one game in 2021, added the extras to make it 19-3 at the break.
Toulouse responded first after the interval as Santiago Chocobares, who was part of the Pumas' training camp in Paris last week unlike Urdapilleta, opened his account for the season.
Despite the quick response, Castres crossed again as Dumora claimed his double with half an hour to play before Urdapilleta was succesful with a fourth penalty of the game.
Toulouse winger Mathis Lebel claimed a 77th consolation try for the visitors, whose focus will quickly move to playing the Bulls next weekend.
Later, the health of French domestic rugby will be highlighted as Bayonne host Pau at a sold-out 40,000-capacity Reale Arena in San Sebastian.
Second-placed La Rochelle then travel to Bordeaux-Begles in front of another full house with 42,000 people expected at the town's football ground, the Matmut Atlantique.
On Sunday, third-placed Stade Francais welcome Racing 92 in the Parisian derby.
