Seven-times champions Olympique Lyon are in danger of being knocked off the top of Ligue 1 on Saturday and injured striker Sidney Govou said the club's poor recent form had dented morale.
Girondins Bordeaux can take over at the summit if they win at Nantes and Lyon fail to take maximum points from a tricky game at neighbouring Grenoble.
"You can't enforce a good atmosphere in a dressing room," Govou told France Football magazine.
"It's there or it's not and in our case it's not. It used to be different but players and their mentality have changed," added the French international who is out for the rest of the season after rupturing his right Achilles tendon in training on Wednesday.
Lyon's lead has been cut to one point after recording only one win in six games.
Twenty matches have been played by the top teams this season. Lyon were six points clear at the same stage last year, 14 ahead in 2007, 12 in 2006 and six in 2005.
Chairman Jean-Michel Aulas said he was worried after the champions were held 1-1 at home by Lorient last weekend.
"It's true we are not playing as well as last season but I'm confident we have the quality and quantity of players to put things right before our next game at Grenoble," said Aulas.
Mid-table Grenoble lost their last league match 1-0 at third-placed Stade Rennes, who have gone 18 games without defeat in Ligue 1.
Two points off the pace, Rennes could also get a chance to take top spot when they visit Lille on Sunday.
Lyon's main challenge, however, comes from Bordeaux who hammered Paris St Germain 4-0 last weekend.
"We were competitive in every area of the game and scored four goals each by a different scorer without conceding any, which is very satisfying," said coach Laurent Blanc.
"It doesn't mean things will not change but it shows we can do it."