Paris Saint-Germain coach Carlo Ancelotti believes his team will need more than just talent to clinch the Ligue 1 title this season.
Despite a 3-2 loss to Sochaux on Sunday, PSG remain top of the table – sitting three points clear of Lyon.
PSG face third-placed Marseille in a crucial league encounter on Sunday and Ancelotti said it would be tough for his side to maintain their form.
"The French championship is special. There is a lot of rhythm, speed and intensity. It is not always easy," the Italian told Ma Chaine Sport.
"In Ligue 1, talent is not enough. The defensive work is the most difficult thing for (Javier) Pastore, (Ezequiel) Lavezzi and Lucas (Moura)."
Ancelotti is wary of Marseille ahead of consecutive matches against Elie Baup's men, in the league and then the Coupe de France.
"Marseille are a beefy team who use many crosses," Ancelotti said.
"They are aggressive and have benefited from their mental strength."