THEY were once touted as the players who were set to catch up with their elders.

Instead, they have fallen off the pace. Rafael Nadal, Novak Djokovic and Andy Murray, now all 24-years-old, were supposed to be pursued by such as Juan Martin Del Potro, Marin Cilic and Ernests Gulbis, all 22. Yet all three have faltered recently.

Del Potro, a grand slam winner in the USA in 2009, can’t be faulted. The Argentinian, who plays Ivo Karlovic of Croatia today, has been knocked off the road to the top by a succession of injuries, most notably to his wrist and hip. He has also won at the very highest level and his defeat of Roger Federer at Flushing Meadows has shown him to be capable of competing at the very highest level. His body may be weak of late but his spirit is willing and his game is powerful and troublesome even to the best players.

But Cilic and Gulbis have been disappointments. In the same US Open that brought a title for Del Potro, the Croat defeated Murray with some ease, seemingly stating his case for elevation into the top rank. But he has only reached ninth in the world rankings and has now slipped to 20th. His record of 21 wins and 11 defeats this season tells the story of player who has settled into a rut of mediocrity. Yesterday he departed in the first round of the French Open, losing lamely to Ruben Ramirez Hidalgo in straight sets, 7-6, 6-4, 6-4.

Gulbis, the son of a Latvian millionaire, suffered a similar fate, being defeated by Blaz Kavcic, 6-1, 6-4, 6-2. It was a trouncing that reflects the slump of Gulbis from coming player to underachiever. Gulbis is now rated 85 in the world, from a high of 21. He has lost 10 matches on tour this season, winning seven. He, too, has suffered from injury but this is the curse of the modern player. But, more tellingly, questions have been asked of his attitude. The fitness will return but Gulbis will need every ounce of gumption to improve.

The ATP tour is ruthless. Players are assessed on results, not promise. This is why a powerful but limited slugger such as Stanislas Wawrinka can profit at a high level. The Swiss player, at 26, will never win a slam or move into the top five. However, he is now rated 15th in the world and showed he is in no mood to regress by beating Augustin Gensse of France, 4-6, 6-3, 6-4, 6-2. Wawrinka could have been forgiven for letting his head droop in the Paris sun when he lost the first set and trudged back to his seat as a partisan crowd roared their approval for his French opponent.

Instead, he buckled down and shrugged off every diversion to win the next three sets easily. “I’m happy, I’m satisfied,” said Wawrinka.’ ‘I was a bit slow. I took some time before I got into the match. But I felt better at the end. I was a bit tense at the beginning.”

He found a way to win and goes on in the tournament. There also victories for Jo-Wilfried Tsonga in three sets against Jan Hajek of the Czech Republic and David Ferrer, by the same margin, against Jarkko Nieminen of Finland. Ferrer threatens to provide Roger Federer with strong opposition in the last 16 if matches go according to form and rankings.

In the women’s tournament, Shahar Peer, the Israeli ranked 19th, fell on the first day but this was the mildest of shocks.