Rafael Nadal vs. Roger Federer: Why Rafa Isn't the Best Ever Yet

As Rafael Nadal continues to break records at an alarming pace and prove he's not just a clay-court master, numerous players and tennis critics have come out and said that he is the best tennis player not only of his generation, but of all time.

But while Nadal is on the cusp of being the greatest tennis player ever, he isn't yet.

If I'm not mistaken, Roger Federer still holds the record for most Grand Slam singles titles, with 16 in his career.

Nadal has 10, and at 25 years of age, it would be hard to see him not surpassing Federer's mark.

But when Nadal injured his foot against Juan Martin del Potro on Monday at Wimbledon, it played right into my point.

When tennis players get older, their athleticism inevitably suffers, and a tennis player should be judged just as much in his late 20's and early 30's (if he gets there) as he is in the early stage of his career.

Federer, during his prime, won five consecutive Wimbledon titles, a mark achieved only by the great Bjorn Borg in the open era.

But he also won the Australian Open last year and the French Open and Wimbledon two years ago in his late 20's.

And he's still going strong. He just beat Novak Djokovic in the French Open this year, halting Djokovic's winning streak in 2011 at 41 straight matches. If Djokovic had beaten Federer, he would have tied John McEnroe for the greatest winning streak to start a season in tennis history.

And that right there showed the mastery of Federer.

He's ranked No. 3 behind Djokovic right now, but in the French Open he proved that he's still the No. 2 tennis player in the world at this point in his career, behind Nadal.

And Djokovic's streak was no fluke. He played one of the greatest stretches that the tennis world has ever seen. McEnroe even said Djokovic's streak was more impressive than his own because Djokovic had to win the Australian Open during his streak.

A tennis player is not only measured by his dominance in a short period, but also by his ability to win when there's no reason to think he can, when his knees are buckling, when his serve isn't what it used to be, or when he can't physically outplay an opponent.

Until Nadal proves that at a late age, Federer will still be the greatest tennis player ever in my mind.