Rafael Nadal's US Open Title Cements Legacy as One of Tennis' Greatest Ever

Rafael Nadal entered the 2013 year on the short list of greatest tennis players of all time, and that's only been solidified by his U.S. Open title win over Novak Djokovic on Monday. 

Nadal won his 13th career Grand Slam title in the process, and his second in a year that many experts thought he would struggle to return to top form after knee problems late in 2012. 

The 27-year-old has a number of years that he'll remain one of the greatest active players, especially with his dominance on clay courts allowing him to win the French Open nearly every year. That's not an exaggeration—from 2005-2013, there was only one year (2009) he didn't take home the championship at Roland Garros. 

His 13 titles put him alone in the third spot all-time behind Roger Federer, first with 17, and Pete Sampras, second with 14. After this year, you'd expect Nadal to be a sure bet to tie Sampras with No. 14 next summer in Roland Garros. 

But it's the questions he answered about whether he could still win away from the more familiar clay courts that stood out from his performance. 

With eight titles at the French Open and only five elsewhere, it's fair to question how great Nadal's chances of upstaging Federer's 17 (or maybe more) are when he can't win outside of France.

But with his first off-clay major win since 2010 and proving to be more healthy than ever, there's no reason to believe Nadal won't pick up a couple more at the U.S. Open or elsewhere. 

Nadal's incredible 2013 campaign wasn't just for the Grand Slam stage, although his two Slams obviously stood out. He had 10 wins on the year and was a perfect 22-0 on hard courts.

With Federer in the twilight of his career, Andy Murray and Djokovic look to be his biggest competition for Slams over the next half-decade. That's only another reason why his win—in a convincing four sets—over the Djoker was so telling. 

If Federer doesn't go out with a couple of Slams, Nadal has more than a slim chance of becoming the best player of all time by the time he puts up the racket.