Lyon's title ambitions took a further knock on Sunday when lowly Nice scored two late goals to ensure the former seven-time champions left the Riviera with a 2-2 draw.
Lyon missed the chance to move second as they stay fourth eight points behind leaders Lille who kept their title push on track Saturday with a 3-1 success over Caen as rivals Rennes and Paris Saint German also lost ground following goalless draws at home.
"It's hard to swallow," said Lyon coach Claude Puel, whose side were also held by Rennes a week ago.
"Without having a great match we lead 2-0 and could have gone 3-0 or 3-1. In the end we gave Nice the momentum.
"We were weak. Given our ambitions and objectives, the Nice draw is difficult to accept. We're furious with ourselves."
Rudi Garcia's Lille now have a seven-point cushion on second-placed Marseille who face a tricky trip to Lens later on Sunday.
Lyon let their guard down late in the game after going into the locker room at half time with a two-goal advantage after Kim Kallstrom opened after 22 minutes and Lisandro added a second just before the whistle.
Nice, now three points above the drop zone, refused to give up with Lyon goalie Hugo Lloris doing well to keep out a Danijel Ljuboja penalty on 50 minutes awarded after the Serbian striker was brought down by Senegalese defender Pape Diakhate.
Lyon were reduced to 10 men when Diakhate was finally given his marching orders after 90 minutes for a second yellow card, with striker Eric Mouloungui netting the penalty.
Argentine defender Renato Civelli levelled the scores three minutes later with a goal which had shades of a hand ball.
Nice coach Eric Roy hailed his team's gutsy performance.
"Lyon scored through two of their rare chances. We had three 3 or 4 opportunities but the score remained in favour of our rivals in the first half," said Roy.
"At the break I told my players to remain focused and they were until the end. Finally it's almost disappointing to take just a point after such a match."
Lille, meanwhile, are showing no sign of weakness as they kept their bid for a first league title since 1954 on track with goals from Aurelien Chedjou (30), Eden Hazard (61) and top scorer Moussa Sow who slotted home his 20th goal of the season after 73 minutes.
Youssef El Arabi got one back five minutes from time, but Caen, who are three points above the drop zone, suffered their third heavy defeat of the season to Lille.
Lille's next match is against relegation-threatened Monaco, who won 2-0 at 10-man Arles-Avignon, as Rennes remain third despite their goalless at home against Auxerre.
The Brittany side have lost momentum in recent weeks, taking just two points from their last three matches, as Auxerre are just above the drop zone in 17th.
Paris Saint Germain have also lost steam, taking two points from their last four games including Saturday's 0-0 draw to Lorient, leaving the Parisians a distant fifth, 12 points behind Lille and five off Rennes.
Elsewhere, Bordeaux stay eighth after a 0-0 draw at 12th-place Nancy.
The situation remains complicated for Brest, who suffered their fourth straight defeat after a last gasp Brown Ideye goal gave hosts Sochaux a 2-1 win.
Montpellier won 1-0 at Toulouse to keep their bid for a Europa League spot alive as European rivals Saint-Etienne one place below were held 1-1 by Valenciennes on Sunday.