Roger Federer has already proved everything he needs to prove in the sport of tennis.
He once spent 237 consecutive weeks as the No. 1 tennis player in the world. He has made over $20 million more than the second player on the career-earnings list. He has won 16 Grand Slam singles titles and counting.
Yet Federer isn't going anywhere but down from here.
Fed-Ex is not the player he once was, but he's the most-skilled player that we have seen at the age of 30 in the history of the sport.
His skill set has hardly fallen off since his 30th birthday, despite what his ranking may show.
He rarely loses to any opponent but Djokovic and Nadal, maybe sprinkling in a failure against Jo-Wilfried Tsonga and Andy Murray from time to time. Everyone has the right to lose to inferior competition on occasion, but we seldom see Federer fall victim to lesser players.
For the most part, he beats everyone he is expected to. Even when he loses to the two players ranked ahead of him, the match is hard fought and compelling for everyone involved.
Tennis is supposed to be a young man's game. The 25-year-old Djokovic and the 26-year-old Nadal serve as proof to support that statement. "Old Man" Federer is looking rather spry on the back end of 30, defying the laws of nature through his ability to compete with the more youthful players.
That isn't something we typically see.
Take Pete Sampras for example. By the time he turned 30 years old, he had fallen all the way to No. 10 in the world. With his 31st birthday approaching, Sampras fell four more spots to No. 14. By the time Sampras turned 31, he had fallen out of the Top 20.
There's simply no way that Federer will deteriorate at a pace rapid enough to see that same decline. He still has the same pep at 30, while Sampras surely did not.
We'll take into account the career of another tennis great as a frame of reference. Andre Agassi was in the tail end of his career by the time Federer surged onto the world stage. He was not able to beat Federer in six tries. Agassi saw numerous dips in his rankings, displaying an almost cyclical level of performance.
The changing of the guard has been much more kind to Federer than it was to Agassi. Federer's contemporaries—Nadal and Djokovic—took much longer to get the best of Fed-Ex.
Not counting matches played on clay—where Nadal is the best of all time—Federer holds an eight-to-six advantage in the series. The majority came before Federer turned 30, but he has beaten Nadal two-of-three times since his 30th birthday.
Federer has shown no signs of slowing down, and has only surrendered his No. 1 ranking because of the abilities of Djoker and Rafa.
It isn't often that we see a talent gap as large as we currently see between the top three players and the rest of the field. It's less often that we are able to lump a 30-year-old in with two players who are four and five years younger—a testament to Federer's greatness.
Federer's fall from grace has been much less rapid than those that came before him. The younger players in the sport are still feeling his wrath in every tournament and will continue to do so for the foreseeable future.
Not too shabby for a father of two, right?