Marseille bounced back from their UEFA Cup defeat to Shakhtar Donetsk to move top of Ligue 1 with victory over Grenoble.
After edging a goalless first half, the home side scored three times in 12 minutes early in the second period to effectively secure the three points.
Taye Taiwo opened the scoring on 52 minutes from the penalty spot after Laurent Batlles was penalised for a foul on Mathieu Valbuena.
Just six minutes later Vitorino Hilton made it 2-0 with his first goal for the club, heading home from Valbuena's free-kick. And the match was over on 64 minutes when Taiwo scored his second of the game with a stunning free-kick from 20 yards which nestled in the top corner.
The home side's fourth goal did arrive in the 89th minute when Arfa found Brazilian Brandao on the edge of the area and he fired a low shot past Wimbee.
Grenoble scored a consolation goal in the fourth minute of injury-time through Laurent Courtois but OM deservedly moved top of the table
Lyon, the seven-time reigning champions, came into their match against Monaco in third place, and the point they secured - courtesy of Frederic Piquionne's 81st-minute leveller - lifted them only one place.
The principality side went ahead through Jerko Leko in the 34th minute and although Cris equalised for Lyon, Juan Pablo Pino's immediate riposte after 65 minutes looked likely to earn the visitors all three points.
Piquionne, with an overhead kick, secured Lyon a draw against his former club but with seven matches left in the campaign, they trail new leaders OM by a point and their grasp on the title they have owned since 2002 is slipping.
Lille and Paris St Germain shared the spoils at the Stade Metropole with a goalless draw that will not do either side's hopes of landing the Ligue 1 title any good.
The home team shaded an end-to-end contest but could not make the most of a number of half-chances they created, especially early on, as they failed to stretch their winning run to five matches.
PSG will be the happier with the draw, which leaves them sixth, level on 56 points with fifth-placed Lille and Toulouse but increasingly adrift of Marseille, Bordeaux and Lyon - the leading three sides in the league standings.
Girondins Bordeaux had taken over from Olympique Lyon at the top of Ligue 1 on goal difference with a 2-0 win at mid-table AJ Auxerre on Saturday.
Bordeaux, who notched a fourth win in a row with goals by Brazilians Fernando and Wendel, are now second on 59 points with seven games left.
Toulouse defeated lowly Nantes 1-0 to climb to fourth place on 56 points thanks to Ligue 1 top scorer Andre-Pierre Gignac, who took his tally to 19 with a 25-metre, left-footed shot that went in off the post.
Lille and Paris St Germain, fifth and sixth on 55 points,