It's safe to say Roger Federer's best tennis is behind him. But is it also safe to say that he's now entering "fading" mode?

In his latest tournament, at the Madrid Masters, Federer actually lost before the quarterfinals there for the first ever. The splendid Swiss had reached at least the round of eight in the Spanish capital in his previous nine trips, including no less than five finals (three titles and two runner-ups). And he was last year's Madrid champion on that goofy blue clay.

Don't look now, but Federer hasn't won a title on the ATP World Tour since last August ... nine months ago. That's an eternity for arguably (perhaps, probably) the greatest player in the history of tennis.

The Fed is 0-for-5 in five events this year and gave way to rising Japanese Kei Nishikori in a third-round affair in Madrid this week. The world No. 16 Nishikori is a really nice player -- a gritty fitness type who I believe is heading for the top 10 -- but he shouldn't be beating Federer on red clay while Federer is still the No. 2 player in the world.

Federer, of course, is so good on clay that he's a former French Open champ who would probably be a five-time French Open winner if a guy named Rafael Nadal wasn't around to beat him in four different finals at Roland Garros.

I hate to say Federer is floundering, considering he's still ranked second (for now) in the world, but his body language hasn't been the same this year, one in which a sore back prompted him to take a nearly two-month respite. His appearance in Madrid marked his first tennis since he suffered a 6-4, 6-2 quarterfinal spanking at the manos of Nadal in Indian Wells, Calif., back in March.

In his Madrid return, the Swiss legend cruised past Czech veteran Radek Stepanek before succumbing to the 23-year-old Nishikori. Federer showed only spells of his well-documented prowess, and blamed windy conditions for his loss against "Special K."

"I'm going to go back to the practice court, train hard and make sure I don't have these kinds of days anymore," Federer said. "At least I'll come out with some ideas of what I need to work on."

Unfortunately, you can't work on getting any younger.

The 31-year-old Federer opened his 2103 campaign with a heartbreaking semifinal loss against U.S. Open champ Andy Murray at the Australian Open and hasn't quite been the same since.

A quarterfinal loss against Julien Benneteau at Rotterdam; a semifinal setback versus Tomas Berdych at Dubai; the Indian Wells QF drubbing by Nadal; and then Nishikori. The latest loss will drop Federer from No. 2 down to No. 3 on the planet, with Murray advancing past him.

And Federer is a mortal 1-3 against top-10 competition this year.

It doesn't look like your typical Federer pattern, a pattern that has seen the Basel native roar to a men's-record 17 Grand Slam singles titles and near- record 21 Masters championships (Nadal has 22).

Last year, Federer piled up six titles, including an unexpected seventh Wimbledon championship, and performed in five other finals, but a disappointing quarterfinal loss against Berdych at the U.S. Open may have been a red flag for the all-time great, who was actually the top seed in New York and hadn't lost before the semifinals there since 2003.

Obviously, Federer's days of domination are in the rear-view mirror, thanks to the likes of Novak Djokovic, Murray and Nadal, of course. I just wonder if his days of still being "Roger Federer" are cooked as well.