Pete Sampras has backed Roger Federer to break his Grand Slam record and has questioned Rafa Nadal's sustainability at the top.
Fourteen-time major winner has no doubt about his world number one
Pete Sampras has backed Roger Federer to break his record number of Grand Slam wins and has questioned Rafael Nadal's future at the top level in the process.
Federer is just one major short of equalling Sampras' record of 14, but endured a disappointing 2008 by his exceptional standards adding only the US Open to his tally.
Nadal captured the 27-year-old's Wimbledon crown and his world number one ranking simultaneously meanwhile, but Sampras has no doubt the Swiss will come back even stronger in 2009.
Record
"There's a lot left in him," Sampras said. "I think he'd like to get back to number one and he's looking forward to breaking my record soon. He'll probably break it over the next couple of years.
"He's a credit to the game, he's a friend and there's nothing I can do about it apart from sit back and watch him do it and respect it."
Five years Federer's junior and already with five grand slam titles to his name, Nadal also looks on course to push the American great's record close but Sampras has raised doubts over the Spaniard's sustainability.
"It will be interesting to see what happens with Nadal next year," added the 37-year-old.
"The amount of work he has to do to stay on top and stay healthy - I think that's where Roger has a bit of an advantage because it takes a lot less energy for Roger to stay on top than Nadal.
Tight
"Rafa's strung so tight and the guy is an absolute animal. He puts so much effort into each point that eventually something will break.
"There's a certain grind that he goes through, unlike Roger who is a lot more fluid and wins matches a lot easier.
"But when you're the best player in the world and people are gunning for you year after year, that's when it takes its toll and it'll be interesting to see how he handles that."
The US legend, who retired from professional tennis at the age of 31, is currently competing in London at the BlackRock Masters.
