Paris Saint-Germain had midfielder Thiago Motta sent off on a frustrating night as it was held 0-0 by relegation battlers Ajaccio on Friday, opening the door for either Lyon or Marseille to move into top spot in the French league.
PSG had won its past four games without conceding a goal to head into the winter break ahead of Lyon and Marseille on goal difference, but this was one of PSG's worst performances of the season as new signing Lucas Moura failed to spark a near lifeless attack.
"It's true that it wasn't a good result for us, but in my opinion the performance wasn't bad,'' PSG coach Carlo Ancelotti said. "(Considering) we had a player less, the second half was good.''
The first half wasn't played with much intensity and we didn't score. We weren't very efficient in front of goal, we should have used the width more.
Top scorer Zlatan Ibrahimovic missed the best chance of the match when he volleyed over from close range midway through the first half and PSG was reduced to 10 men moments before the break when Motta clattered into midfielder Frederic Sammaratino from behind and was shown a straight red - PSG's fifth red of the season.
"I didn't see it so I can't say anything about it,'' Ancelotti said. "I think it's a lot. It's either our fault or the (fault of) the referees. I don't know.''
But Ancelotti did admit that PSG's attacking play was disappointing considering the team included Ibrahimovic, Argentina winger Ezequiel Lavezzi, Moura and Argentine playmaker Javier Pastore - more than ?130 million ($170 million) worth of combined talent.
"Yes, it's strange, but that's football,'' Ancelotti said. "We lacked precision.''
PSG is one point ahead of Lyon and Marseille and could be overtaken by them this weekend. Both are up against teams in the relegation zone, as Lyon visits Troyes on Saturday and Marseille visits Sochaux on Sunday.
Earlier, Saint-Etienne was held to a 2-2 draw by Toulouse.
At Parc des Princes, Motta headed over and center half Alex saw his header blocked by his own teammate, Lavezzi, early in the match.
Ibrahimovic then missed a great chance in the 25th minute when he had only goalkeeper Guillermo Ochoa to beat as he ran onto Javier Pastore's lobbed pass, but the imposing Swede tried an extravagant lob from five yards (out) and the ball sailed over the crossbar.
PSG generally lacked creativity in a dour first half and things got worse for Ancelotti's team when Motta was shown a straight red card for a dangerous lunge on Sammaratino's ankle as he beat him for pace down the right.
Brazil center half Thiago Silva limped off injured early in the second half with a thigh injury and was replaced in PSG's defense by Mamadou Sakho.
Ochoa denied Alex with a superb leaping save to his left and then rushed off his line well to thwart Ibrahimovic in the second half's only chances as PSG pushed for a breakthrough that looked increasingly unlikely.
Ibrahimovic blasted a free kick over and volleyed wide in the last 15 minutes as frustration grew, and Moura - who cost in excess of ?40 million ($52 million) when he joined from Sao Paulo went off with cramp as his eagerly awaited debut fizzled out on a cold night.
"The credit goes to the players,'' Ajaccio coach Albert Emon said. "This feels like a victory for us against a team like PSG. Every point is valuable at this stage of the season.''
Meanwhile, Saint-Etienne ended a five-game scoring drought as it came from behind to scrape a draw.
Midfielder Loic Perrin put Saint-Etienne ahead in the 26th minute but midfielder Etienne Didot equalized for Toulouse a minute later and right back Serge Aurier put the visitors ahead shortly before halftime.
New signing Yohan Mollo leveled for the home side in the 62nd, but the draw left Saint-Etienne languishing in mid-table after a bright start to the season. Toulouse is a point behind in 11th place. Ajaccio is in 15th spot.