Roger Federer says he is on the verge of beating clay-court rival Rafael Nadal as he begins his chase for the elusive French Open title next Sunday.
Federer, who dramatically lost to 2005 champion Nadal in Rome, hopes to complete his Grand Slam set in Paris.
"I would think it's between the two of us," said the 24-year-old Swiss star.
"I've never beaten him on clay but every time I've played him I've got closer and closer and I should have won in Rome."
Federer holds the US Open, Australian Open and Wimbledon titles, but has never won the French Open.
"He's going to be the big, big favourite for the French Open"
However, he knows Nadal is his greatest obstacle to victory at Roland Garros.
"He's going to be the big, big favourite for the French Open," added Federer, who suffered his fourth successive defeat against Nadal in an exhausting five-hour Rome Masters final earlier this month.
"I really hope we do play (in Paris). I need to play him a little more often to figure him out, and that's what I've had."
Both Federer and 19-year-old Nadal pulled out of last week's Hamburg Masters after their epic encounter in Rome.
And Federer believes the rest has done him good as he prepares for his test at the French Open.
"I got sick too, a little bit, a sore throat and a cold, so it was definitely the right choice not to play. Now I feel fine. I'm on good form."