Federer stumbles, loses again to Nadal in Grand Slam showdown.

A descent that started in 2008 has taken another step in early 2012: Roger Federer is leaving the class of the elite men's tennis players. It is testament to him that he has stayed in shouting distance of Rafael Nadal and Novak Djokovic this long. Federer lost a grueling and hard-fought semifinal match against Nadal (7-6, 2-6, 6-7, 4-6) at the Australian Open on Thursday. 

Right now, Nadal and Djokovic are the kings of the court. Federer is only 1-4 against Djokovic in their last five meetings, though he still owns the 14-10 edge in their career series. Nadal has dominated Fed, 18-9 in their career series and 10-3 since 2008. When you're Roger Federer, competing with and beating the best is all that matters. He just can't do that any more, at least not with the regularity he once did. 

Federer's career will go down as perhaps the most successful in history. His 814 wins, 70 singles titles and 16 Grand Slam titles are astonishing, but all runs must come to an end. Federer is slowly giving way to the next generation. The process has been so slow that his status as viable contender has lasted well in to the younger Nadal's career.

Will he hang on too long like another great before him, Ivan Lendl? Hopefully not. Lendl's dominance and winning percentage were similar to Federer's. Both won nearly 82 percent of their matches, but Lendl played about three years longer than he should have. No one wants to see Federer come into a Grand Slam as an eighth seed, but that is what will happen if he continues to play much longer.

Lendl turned 30 in 1990 and he won the Australian Open that year, but it was the last Grand Slam tournament he'd ever win. Federer is 30 now, and it seems his career has hit its peak and is now regressing. This should be his final year on tour.

Just as Lendl gave way to Pete Sampras and Stefan Edberg, Federer is reluctantly submitting to Nadal and Djokovic. It is the nature of the sport, and even a player as great as Federer isn't immune to the process.