Argentina winger Santiago Cordero scored two tries as Bordeaux-Begles regained first place in the French Top 14 with a 27-23 victory at Pau as Toulon held title holders Toulouse to a 13-13 draw.
Bordeaux-Begles had temporarily dropped to second spot following Lyon's convincing victory over Bayonne on Saturday but they are now two points clear.
Pau, who were without suspended ex-All Blacks full-back Ben Smith, move up to 10th thanks to a late bonus point.
"Obviously being the leaders in December is good but what we want is to be top at the end of the season," Bordeaux-Begles coach Christophe Urios said.
"The game went as I imagined, apart from the last 10 minutes, which we could have managed better," he added.
Australia back-rower Scott Higginbotham crossed for the visitors on 23 minutes after Antoine Hastoy had slotted an early penalty for the home side at the Stade du Hameau.
Pau, without a league win since November 9, were back in the lead less than 10 minutes later with Vincent Pinto's effort.
But Cordero, 24, touched down twice in a 10-minute spell either side of the break after two clever kicks from one-time France international Mathieu Jalibert.
Bordeaux-Begles were awarded a penalty try with 20 minutes to go after pressure inside the Pau half but the home side closed the gap to 27-20 on 67 minutes as New Zealander Daniel Ramsay dotted down.
Despite Pau's late efforts, including a Hastoy penalty which clinched a defensive bonus point, the travelling side held on to go back to the top and stretched their unbeaten run to eight matches in all competitions.
- Champions held by Toulon -
Three-time European Cup winners Toulon held defending champions Toulouse to a 13-13 draw thanks to Anthony Belleau's late penalty goal in front of 33,000 spectators at Le Stadium.
The home side's Sebastien Bezy put his hand up for selection in France's Six Nations squad to be named on January 8 with a 50-metre individual effort and Thomas Ramos slotted a conversion and two penalties for a 13-0 lead after 43 minutes.
Patrice Collazo's visitors roared back to score 13 unanswered points in the final 29 minutes including Belleau's effort to clinch the draw to stay in third place.
Les Bleus scrum-half Antoine Dupont made his first appearance for Toulouse since suffering a back injury at the World Cup in October.
"It's getting better, I took my time to recover, I hope it doesn't come back," Dupont told Canal Plus.
"Toulon were ambitious, they played an away match perfectly," he added.
Elsewhere, La Rochelle scored six tries as they hammered Agen 40-8 and Clermont survived a valiant Castres second-half fightback to win 39-22.
On Saturday, South Africa World Cup winner Handre Pollard scored his first try for Montpellier in a 20-20 draw with bottom side Stade Francais.
Young France fly-half Matthieu Jalibert set-up both of Santiago Cordero's tries as Bordeaux-Begles moved back to the summit of the Top 14 table
Toulouse's Antoine Dupont made his first appearance since injuring his back during the World Cup in October