Montpellier took over from Paris Saint-Germain at the Ligue 1 summit after a second-half onslaught inspired by Olivier Giroud swept them to a 3-0 win at home to Ajaccio on Saturday.
Ajaccio had gone six games unbeaten prior to the encounter at Stade de la Mosson and they frusttated Rene Girard's side in the first half, with visiting goalkeeper Guillermo Ochoa equal to everything the hosts threw at him.
However, Montpellier assumed the upper hand in the second period, with Younes Belhanda breaking the deadlock via a cool chipped penalty in the 53rd minute after Benjamin Andre had tripped Henri Bedimo inside the penalty area.
Giroud teed up Remy Cabella for the second goal in the 64th minute and Ligue 1's top scorer claimed his 16th goal of the season three minutes later, chesting down Marco Estrada's lofted pass and beating Ochoa with a crisp finish.
The result means Montpellier are still to concede a goal in all competitions in 2012 and they now lead the table on goal difference prior to PSG's trip to second-bottom Nice on Sunday.
Meanwhile, Lyon's recent momentum deserted them as they were prevented from leapfrogging Lille into third place by a shock 2-1 loss at home to Caen.
Romain Hamouma opened the scoring in the 13th minute, racing behind the Lyon defence to collect Pierre-Alain Frau's pass and fire a low shot past Hugo Lloris into the bottom-left corner.
Caen had been without a win in Ligue 1 since November 6 but they sealed victory in stunning fashion in the 73rd minute, substitute Livio Nabab scoring with a sublime dipping volley from just outside the Lyon area.
Lisandro Lopez pulled a goal back from the penalty spot with four minutes to play.
Lyon, who host Cypriot side APOEL in the first leg of their Champions League last 16 tie on Tuesday, had won six of their last eight games in all competitions but could fall three points behind Lille if the champions beat Bordeaux on Sunday.
Victory lifts Caen three places to 14th, while they -- like Lille -- also have a game in hand.
A header in injury-time by Swiss international Innocent Emeghara earned 10-man Lorient a 1-1 draw at Auxerre that prevented the hosts from registering a first league win since December 11 and kept them mired in the relegation zone.
Defender Willy Boly had put Auxerre in front in the 18th minute and two minutes later Lorient had goalkeeper Fabien Audard sent off for handling the ball outside his area.
Valenciennes, who knocked holders Lille out of the French Cup in mid-week, edged Nancy 1-0 in their mid-table encounter thanks to an injury-time goal by substitute Mamadou Samassa.
Rennes can draw level with Lyon in fourth place if they beat bottom club Sochaux later on Saturday, while Dijon travel to Brest in the late game.
The extreme cold weather currently assailing France has played havoc with the weekend's Ligue 1 schedule, prompting several matches to be brought forward and forcing the postponement of Marseille's trip to Evian.