Former Wimbledon champion Pat Cash believes that Rafael Nadal could become more successful than Roger Federer.

The Spaniard now has 13 Grand Slam titles to his name following his four-set victory over Novak Djokovic in the US Open final yesterday.

Federer leads the way with 17 titles, but Cash is confident that the 27-year-old can set a new record in the coming years.

"Nadal could surpass Federer's total of 17," BBC Sport quotes Cash as saying. "That debate over who is the greatest is fun but pointless, but you can't argue with eight French Opens and maybe more to come."

Federer was knocked out of the US Open in the fourth round by Tommy Robredo.