Roger Federer waves to fans after practice in Monte Carlo
Roger Federer may have lost his place at the top of the rankings but he remains a supremely formidable opponent, his rivals have said.
The Swiss star has not won a tournament this year and smashed a racquet in an out-of-character outburst in Miami.
"He's made a Grand Slam final and two Master Series semis," said world number one Rafael Nadal.
"He won it all for four years and now he loses a few - he's not in crisis," said world number three Novak Djokovic.
"I did find it strange that he broke his racquet in Miami, he who always keeps calm. But these things happen when you are frustrated on the court," added the Serbian.
Federer, 27, has won 13 Grand Slam events but only one, last year's US Open, out of the last five.
Nadal replaced Federer at the top of the rankings last August, and the Swiss player has never beaten him at a Grand Slam event outside of SW19.
The normally reserved Federer burst into tears after losing to Nadal in the Australian Open final in February, providing the critics with further ammunition that the Swiss player's game was in decline.
France's Gilles Simon has beaten Federer on each of the two occasions they have met, but the Frenchman was equally complimentary as Nadal and Djokovic. "To me, on a good day, he still is the best player in the world," he said.
Breaking ranks, Fernando Verdasco of Spain suggested Federer was struggling psychologically with having to accept he was no longer as dominant as he had once been.
"Two years ago he was winning everything. Now, since the beginning of the year, he has been beaten by Nadal, Djokovic and Andy Murray. Mentally it is not easy to handle."
Federer is due to start his clay-court season in Monte Carlo against Italian Andreas Seppi on Wednesday.