Paris - Stan Wawrinka said Rafael Nadal was back at the peak of his powers after storming to an incredible 10th French Open title on Sunday.
Swiss third seed Wawrinka was trying to win his second Roland Garros title in three years but was blown away by Nadal 6-2, 6-3, 6-1.
"For sure he's playing the best he's ever played. That's for sure. But not only here," said Wawrinka, who lost for the first time in four Grand Slam finals.
"I think since the beginning of the year, you can see he's playing more aggressive, staying more close from the line.
"But that's clearly his best he ever play. That's why he's winning so much again."
Wawrinka admitted the daunting mental challenge of facing Nadal on his favourite surface contributed heavily to the crushing defeat.
"He's playing his best level on clay. Five-set match, you know, it's going to be a really tough challenge when you play against him," said the Swiss.
"I didn't play my best tennis for sure, I was a little bit hesitant with my selection of shots.
"When you play against Rafa, if you hesitate, it's no good. If you hesitate for half a second, it's too late. You will be late.
"Physically I felt good, but mentally it was tough."
Wawrinka arrived in Paris fresh off winning a clay court title in Geneva and knocked out world number one Andy Murray in a five-set thriller in the semi-finals.
But the 32-year-old, the oldest Roland Garros finalist in 44 years, had no answers as Nadal eclipsed Pete Sampras on the all-time list of major champions with 15 titles.
"He's an amazing fighter. On clay he's just tough to play. There is always one ball coming back. He creates doubts that you cannot have if you want to beat him.
"I think today, if you play Rafa, if you're not completely free with what you think and what you're gonna do and not completely relaxed the way you're gonna play, you have no chance."
Nadal won for the 16th time in 19 meetings with Wawrinka, who insisted there was plenty to be positive about following his recent performances.
"In three weeks I won Geneva and made final of a Grand Slam, so that's big for me," said Wawrinka, who will rise a spot to third in the rankings.
"But I will need few days to really see that, because it's tough to describe the feeling of losing a Grand Slam final."