One would be hard pressed to find anyone who believes that Roger Federer has anything left to prove on a tennis court.
With 17 Grand Slams over a 10-year period, and at least one title in each year from 2003-2010, Federer has dominated the sport like no one ever has, but even at 31, the Swiss star is trying desperately to add to that total.
It hasn't been easy lately.
Sure, he won Wimbledon last summer, and advanced to the Olympic final weeks later.
But since then, Federer has failed to advance to the final at both the 2012 U.S. Open and this month's Australian Open, including his first quarterfinal exit at Flushing Meadows since 2003.
If it weren't for the gradual emergence of Andy Murray over the last nine months, Federer would still be finding himself with a chance at the 2013 title in Melbourne. Until the London Games, Federer had ousted Murray in every one of their meaningful duels, including all three of their meetings at Grand Slams.
Now, though, Murray suddenly appears to have Roger's number, as the Scot knocked Federer off in straight sets at the Olympics, and more recently, in a five-set bloodbath in Melbourne.
And even if Federer can find a way to a Grand Slam final by either beating Murray or avoiding him, it's all but certain that he'll have to get through Novak Djokovic, which has proven to be an even more difficult task.
Despite Federer's impressive four-set triumph over Djokovic at Wimbledon last summer, the Serb has held the definitive upper hand in recent years, taking four of their last six meetings at Grand Slams.
That's not to say that Federer can't win another Slam, it's just not a sure thing at this point in his career.
He's still consistently reaching the semifinals at virtually every important tournament, and it's not as if he's incapable of knocking off Murray, Djokovic, or even Rafael Nadal if he ever comes back, but he's never going to waltz to a Grand Slam title like he did for so long.
So, looking ahead to the remaining three Slams of the year, what's realistic for Federer in terms of title hopes?
Probably at least one berth in a final, but it won't be before the beginning of July. Yeah, it's only been four years since Federer took the title at Roland Garros, but that's the only time he's won the French Open and it's unlikely he will again.
In theory, Federer's best shot at a Slam is obviously at the All England Club, because it's the tournament he had a stranglehold on for seven years (six titles during that span), not to mention the fact that he's the defending champion.
It's also conceivable that Federer could come close to a title at the U.S. Open as well, but given that it's the final tournament of the year, he may not be as fresh as his younger rivals.
Regardless of whether he wins again, Federer's legacy as the greatest of his generation will remain untouched, but he still might add one more coveted title to his trophy case in 2013.