Roger Federer admits he would not have been able to beat the "gigantic" Rafael Nadal at Roland Garros on Sunday.
Nadal produced a dominant display to overcome Stan Wawrinka in the French Open final and finish the tournament without dropping a set, becoming the first man to win 10 titles at the same grand slam in the Open Era.
The Spaniard's performance in Paris marks a magnificent return to form for Nadal following his struggles with injury over recent seasons.
Eighteen-time grand slam winner Federer has won each of his last four meetings with Nadal, including in the finals of this year's Australian Open and Miami Masters, but concedes Nadal is the master of clay-court tennis.
"I wouldn't have beaten Rafael Nadal yesterday at Roland Garros. Not in the shape I would have performed on clay," he said.
"I told him on the court in Miami that he will destroy this season on clay. Luckily I was right for once. He played great.
"What Rafael achieved didn't surprise me at all, as he showed in Australia what is possible for him on clay.
"But that he ran through the tournament like this is absolutely gigantic."