Marseille moved level on points with PSG thanks to a narrow 1-0 victory over 10-man Lille at Stade Velodrome.
All the key action took place in the space of two minutes around the interval as Lille's Florent Balmont saw red in first-half stoppage time before Jordan Ayew netted the only goal a minute after the restart.
OM move onto 26 points, level with PSG but second to the capital club on goal difference. Lille are ninth as their inconsistent campaign continues.
Marseille welcomed controversial midfielder Joey Barton into their line-up for the first time in Ligue 1 following the expiry of his 12-game domestic ban.
Lyon's annual capitulation at the Stadium Municipal saw Wissam Ben Yedder bag a brace as Toulouse climbed up to seventh with a 3-0 win.
Ben Yedder's double and Etienne Capoue's last-minute strike goal made it 11 goals conceded without reply from Lyon's last seven trips to the south west, as Remi Garde's men, who remain in third, also missed the opportunity to dislodge Paris St Germain from the top of the table.
Nancy remain rooted to the bottom of the table after they could only draw 1-1 with mid-table Ajaccio at the Stade Marcel Picot on Saturday.
Djamel Bakar put the home side ahead after seven minutes, but it was a lead they could not hold onto as Adrian Mutu tucked a penalty away 15 minutes before the end after Romain Grange handled in the area.
The result leaves Jean Fernandez's side seven points off safety and with just one victory to their name so far.
Bastia defiantly hauled themselves clear of the relegation zone as they snatched a 2-1 win from Lorient despite playing almost the entire match a man short.
Anthony Modeste went from hero to villain as he opened the scoring on 11 minutes only to see red moments later.
The striker was perhaps unlucky to be dismissed, after he dived in on Kevin Monnet-Paquet, but Bastia looked set to be punished nonetheless when Lamine Kone levelled on the half-hour.
But rather than roll over the Corsicans immediately grabbed back the lead through Wahbi Khazri before holding the visitors at bay for an hour to move three points clear of the drop zone.
Evian climbed to 15th place courtesy of a 1-0 victory at the Stade de la Route de Lorient, ending Rennes' four-match winning run.
Substitute Zouheir Dhaouadi netted the game's only goal 11 minutes from time to earn the visitors only their fourth win of the campaign.
Brest finally claimed their first away point of the season and may feel they deserved to take all three after enjoying the better of their 0-0 draw with Reims.
The visitors went into the match with the worst away record in Ligue 1, losing all seven of their matches and scoring just three goals in the process, but they were able to lay that ghost to rest at Stade Auguste Delaune.
Nice moved into the top half after Dario Cvitanich's first-half penalty inspired them to a 1-0 win at struggling Sochaux.
Cvitanich netted from the spot to give the visitors a deserved lead on the stroke of half-time after Roy Contout was adjudged to have handled in the area.
On Friday night, Romain Hamouma's second-half strike proved the difference as St Etienne claimed a narrow 1-0 victory over fellow high-flyers Valenciennes.
Both sides had the chance to move to the top of the standings ahead of Saturday and Sunday's action with a win but it was the hosts who prevailed as they extended their unbeaten run to nine matches.
They dominated throughout at the Stade Geoffroy-Guichard and deservedly sealed all three points when Hamouma netted after Valenciennes had failed to clear their lines in the 73rd minute.
On Friday night, Romain Hamouma's second-half strike proved the difference as St Etienne claimed a narrow 1-0 victory over fellow high-flyers Valenciennes.
Both sides had the chance to move to the top of the standings ahead of Saturday and Sunday's action with a win but it was the hosts who prevailed as they extended their unbeaten run to nine matches.
They dominated throughout at the Stade Geoffroy-Guichard and deservedly sealed all three points when Hamouma netted after Valenciennes had failed to clear their lines in the 73rd minute.
Nancy remain rooted to the bottom of the table after they could only draw 1-1 with mid-table Ajaccio at the Stade Marcel Picot.
Djamel Bakar put the home side ahead after seven minutes, but it was a lead they could not hold onto as Adrian Mutu tucked a penalty away 15 minutes before the end after Romain Grange handled in the area.
The result leaves Jean Fernandez's side seven points off safety and with just one victory to their name so far.
Bastia defiantly hauled themselves clear of the relegation zone as they snatched a 2-1 win from Lorient despite playing almost the entire match a man short.
Anthony Modeste went from hero to villain as he opened the scoring on 11 minutes only to see red moments later.
The striker was perhaps unlucky to be dismissed, after he dived in on Kevin Monnet-Paquet, but Bastia looked set to be punished nonetheless when Lamine Kone levelled on the half-hour.
But rather than roll over the Corsicans immediately grabbed back the lead through Wahbi Khazri before holding the visitors at bay for an hour to move three points clear of the drop zone.
Evian climbed to 15th place courtesy of a 1-0 victory at the Stade de la Route de Lorient, ending Rennes' four-match winning run.
Substitute Zouheir Dhaouadi netted the game's only goal 11 minutes from time to earn the visitors only their fourth win of the campaign.
Brest finally claimed their first away point of the season and may feel they deserved to take all three after enjoying the better of their 0-0 draw with Reims.
The visitors went into the match with the worst away record in Ligue 1, losing all seven of their matches and scoring just three goals in the process, but they were able to lay that ghost to rest at Stade Auguste Delaune.
Nice moved into the top half after Dario Cvitanich's first-half penalty inspired them to a 1-0 win at struggling Sochaux.
Cvitanich netted from the spot to give the visitors a deserved lead on the stroke of half-time after Roy Contout was adjudged to have handled in the area.
