Rafael Nadal has lamented "all the issues I went through in my career" as he attempts to get up to speed at the Italian Open.
The Australian Open champion has endured a spate of injuries since his memorable triumph at Melbourne Park and is preparing for the French Open in Paris later this month.
The 35-year-old, who has 21 Grand Slam singles titles to his name, is in last-32 action on Wednesday in Rome having been seeded number three for the clay-court event.
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Speaking ahead of his tilt at glory at the ATP Masters event, Nadal bemoaned the fact that "my body is like an old machine" after comparing himself to his young compatriot, Carlos Alcaraz, by saying "a new car always looks better".
"When you're six weeks without touching a racquet and having the chance to move your body ... my body is like an old machine. To put this machine on again it takes some time," Nadal told reporters at the event.
"It's not the same when you're 19 than when you are almost 36, with all the issues I went through in my career.
"You need to build again the confidence, your movements, then you start feeling comfortable with your tennis.
"It's more about being confident with my movements, recover the speed, recover the way that I have to play on clay and let's see.
"I'm confident that I can play well. I need time, but maybe this week can be a positive week, maybe not. Who knows?"

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Nadal lost out to his great rival, Novak Djokovic, at Roland-Garros in a classic semi-final clash last year, but he is determined to be fully prepared for his favourite event, which gets underway on May 22.
"That's my goal ... I didn't have another chance to approach this clay-court season with the things I went through," he said.
"I'm going to give myself a chance and we'll see what's going on."
Speaking about Alcaraz earlier at the event, Nadal said: "First, I think he is young, he is new and all the new things are much more interesting than older things.
"Without a doubt, when you see a new car, always looks better," he said of his countryman.
"When you see a new phone, always looks better than the old ones.
"So, it's something that is normal in this life. I can't complain at all about that. At the same time, I am happy to have somebody like him from my country achieving all the things that he is achieving."

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