Marseille kept their perfect start to the French league season going on Sunday as a Jordan Ayew header, finishing off an assist from brother Andre, secured a fifth straight success in a 1-0 win at Nancy - a club record from the off.
Lyon had briefly taken over pole position earlier in the day after a 2-0 win over Ajaccio achieved courtesy of goals from Dejan Lovren and Lisandro.
That win was Lyon's fourth in five matches and moved the eastern side onto 13 points from five games, but Marseille went two points clear after Ayew connected powerfully with a cross from his sibling eight minutes after the restart.
Cameroon keeper Guy Ndy Assembe did his utmost to keep 2010 champions Marseille at bay as the visitors attacked at will.
He made a pair of fine stops from Andre-Pierre Gignac in the early stages and when it seemed an Andre Ayew effort had him beaten but Vincent Muratori saved the day on the line.
Nancy scrapped hard and visiting keeper Steve Mandanda did well to preserve his clean sheet and Marseille's lead as he saved a meaty free kick on the hour from Yohan Mollo.
Marseille joined Monaco, Bordeaux and Metz as the only sides in French league history to post five wins in the opening five league games.
It was also their fifth straight success at Nancy.
It was a case of deja vu for the former European champions' coach, Elie Baup, who was at the helm of that Bordeaux side in 1999 and the Girondins went on to lift the crown.
For Nancy, it was a third straight defeat and they are now fourth bottom - level on points with reigning champions Montpellier, who have made a desperate start to the new season.
Friday's 3-1 loss at promoted Reims was Montpellier's third of the campaign and they hardly look equipped at the moment to embark on a Champions League campaign which starts with a home match against in-form Arsenal on Tuesday.
Lyon thanked Clement Grenier's corner routine for Lovren's headed opener in the 25th minute and former Fulham man Steed Malbranque then fed Lisandro for a rasping second.
"We turned in a serious showing tonight," said Lyon coach Remi Garde.
"I really enjoyed the first half - not conceding a goal is the foundation."
Corsican outfit Ajaccio were deducted two points over incidents during an encounter with Lyon last season and were unable to pull back some of that deficit Sunday as they finished well beaten.
New signing Adrian Mutu, formerly of Juventus and Chelsea fame, was unable to make a difference in attack, only earning a yellow card for his efforts.
Earlier, nine-man Lorient won 2-1 at 10-man Rennes in a card-strewn Brittany derby to climb to third and leave their local rivals in the bottom three.
Burkinabe midfielder Alain Traore was the visitors' match-winner, putting Lorient ahead with a fine 30-yard lob in the 23rd minute and extending their lead just before half-time with a ferocious free-kick that swerved into the top-left corner.
Lorient had Maxime Baca sent off for a two-footed lunge at Jonathan Pitroipa in the 31st minute and then saw goalkeeper Fabien Audard dismissed for a foul on the same player eight minutes into the second half.
Pitroipa reduced the arrears in the 71st minute, but Rennes' momentum was clipped seven minutes later when substitute Cheick Diarra saw red for an ugly high foul on the impressive Traore.
Lorient are two points ahead of Paris Saint Germain, who beat Toulouse 2-0 at home on Friday to stand joint fourth on nine points with Bordeaux.