Nadal fears he may not be fully fit for US Open

Spain's Rafael Nadal practises at the centre court in Montreal after returning from a two-month lay-off when he was suffering from tendinitis in both knees.

MONTREAL // Rafael Nadal is making his come back from a long injury lay-off at the Montreal Masters this week, but the Spaniard is not sure he will be able to regain full fitness in time for the US Open. Nadal has been out of action for two months with knee problems during which time he lost his French Open and Wimbledon titles and the world No 1 ranking to Swiss rival Roger Federer.

But he said: "I can't tell you if I'll be 100 per cent for the US Open. "It depends on many factors but clearly, I'll work as hard as I can try to be in condition there. But most of all, I want to make sure my knees respond well. "Once I know my knees will repond well, I can train well, I can compete with greater calm and that's what will give me, little by little, the confidence to train at the maximum level," he said.

The US Open, the only grand slam that Nadal has yet to win, starts on August 31 at Flushing Meadows, New York. The Spaniard has been suffering from tendonitis in both knees and has not played a competitive match since being knocked out in the fourth round of the French Open by Swede Robin Soderling on May 31. Nadal pulled out of Wimbledon just three days before the tournament was due to begin but said he was now ready to begin the fight back to his best form.

"I arrived at two very important tournaments this season - Roland Garros [the French Open] and Wimbledon - without my best condition, but for the rest I am here and I am very happy to come back on court with the best motivation to work hard to try to play my best tennis as soon as possible. "I know it is going to be tough in the beginning because after two months outside of competition it's always tough to come back after an injury but I am going to be ready to work very hard as soon as possible," he added.

Nadal has blamed his injuries on the congested calendar for leading players but admitted it would be a tough process to reform the schedule. "Well, it's clear that the calendar can't be perfect for everyone but I think that we - the players and the ATP [Association of Tennis Professionals] - are working hard to try to develop the best possible one for the players and for the tournaments. I think that everyone knows that starting on January 1 and ending on December 5 is too long of a calendar but it's not easy to fix because there are many tournament interests at play and everything is very difficult. We can't scorn any tournament."

Nadal could face the ultimate fitness and mental test here, with world No 1 Federer confirming on Friday that he would compete in the event. * Reuters