London - Roger Federer claims Rafael Nadal's vulnerability on grass will be a significant boost to his chances of winning Wimbledon for a record-breaking eighth time.
After reigning supreme at Wimbledon for so long, Federer has reached only one of the last four finals at the All England Club and suffered a humiliating second round defeat last year against unheralded Ukrainian Sergiy Stakhovsky.
But the 32-year-old is back in south-west London confident of breaking his tie with Pete Sampras for the most Wimbledon titles, with his spirits raised by winning the warm-up event at Halle, where world number one Nadal once again looked uncomfortable on grass in a dismal straight sets defeat against journeyman Dustin Brown.
That was Nadal's third successive loss on grass after his embarrassing Wimbledon defeat against Belgium's Steve Darcis 12 months ago and an equally chastening exit at the hands of Lukas Rosol in 2012.
Nadal faces a tricky first round tie against Martin Klizan and world number four Federer believes the second seed will have to tread carefully as he tries to find his feet on grass in the opening rounds.
"I think he might be slightly more vulnerable in the early rounds," Federer told reporters at Wimbledon on Saturday.
"This new, fresh, lush grass, we're not quite used to it. As you go deeper in the tournament, it becomes easier to move; the ball bounces a bit higher; it becomes more what we're used to.
"The early rounds are key for most of the top guys. We're talking about the first two rounds in particular.
"I didn't expect him to lose last year first round, let's be honest. So these losses, they happen.
"I didn't check his draw, but if he gets through that, I would think we'll see more of what we've seen in the past, is my opinion."
Nadal does have two Wimbledon titles and five final appearances to his name, but unlike at the French Open, where the Spaniard has been the dominant figure for years, 17-time Grand Slam champion Federer is convinced he is still the pre-eminent force at the All England Club.
If Nadal avoids another early exit, the pair are scheduled to meet in the semi-finals and Federer's buoyant mood suggests he will have no fears about taking on the 28-year-old, who was recently crowned French Open champion for the ninth time, despite his poor head-to-head record.
"I feel like if things click here I should be able to win the tournament; whereas at the French I feel like I'm slightly more dependent on Rafa. He's the only guy really," Federer said.
"That doesn't mean I don't believe I can win the French either. It's just that I know he's been so dominant over there that it goes through him regardless; whereas on the grass or hard courts you don't feel it as much.
"I feel like if I play my game it's more on my racquet. As soon as that's the case, you're more confident in your chances.
"I feel I have a very good chance again this year."
Federer expects defending champion Andy Murray to pose one of the greater threats to his hopes of yet another Wimbledon title.
Murray last year became the first British man to win Wimbledon for 77 years and Federer is sure the Scot will be a danger now he has recovered from last year's back surgery.
"Clearly in a perfect world you don't want to have surgery, but I think he's good enough now to defend again; whereas a few months ago honestly I wasn't sure about that," Federer said.
"Defending champion is never an easy thing. But then again, he played so well on grass the last few years. So he knows how it's done, and I would feel comfortable if I was Andy at this point."