Roger Federer: 16-Time Grand Slam Champion Will Fall in US Open Quarterfinals

Roger Federer, the greatest men's tennis player ever, will not make the semifinals of the US Open for the first time since 2003.

While he's had a favorable draw so far, it's about to get a lot harder, and Federer just isn't in good enough form to pull through it like he did in his prime. A loss would represent a changing of the guard at the top of the men's game, and it's one that has been expected for quite some time.

After making the semifinals in every major from 2005 to 2009 (think about that for a second), Federer has bowed out in the quarterfinals in three of the past seven tournaments. The US Open will make that No. 4 out of eight.

He should have no problem dispatching Juan Monaco in the fourth round. The Argentine just doesn't have enough weapons to upset Federer, even at this stage of his career.

His next match, against either Mardy Fish or Jo-Wilfried Tsonga, will be the end of the road for Federer. Both players have played well in the Open and are primed to show Federer the exit in the quarterfinals, which would have been an unthinkable statement a few years ago.

Fish is America's best chance to win a major since Andy Roddick took Federer to five sets at Wimbledon in 2009. He's in the best shape of his life and has been at the top of his game throughout the summer hard-court season.

The Minnesota native knocked off Tobias Kamke and Malek Jaziri in the first two rounds with relative ease before surviving a tough test against the big-serving Kevin Anderson of South Africa.

He hasn't played anybody with the athletic ability of Tsonga, though. Fish will need to stay on the offensive because if he falls back into a defensive shell like he did early in the season, Tsonga will hit enough winners to advance.

Tsonga, like Fish, has had only one difficult match so far. He dispatched Yen-Hsun Lu and Sergei Bubka before facing the Spanish lefty Fernando Verdasco in the third round. The fabulous Frenchman made it look easy, taking the match in three sets.

That sets up an awesome fourth-round duel between Tsonga and Fish. Tsonga is the slight favorite, according to 5dimes.com, but Fish will have the Arthur Ashe Stadium crowd behind him.

Assuming the encounter doesn't take so much out of both men that the winner doesn't have anything left for Federer, the former world No. 1 is in trouble.

It's trouble that Federer has become much more accustomed to over the past two years, which illustrates that the end of his dominating run is closer than ever.