While Nadal emerged this year as Federer’s toughest opponent on any surface, mononucleosis provided his stiffest challenge. The virus that causes the illness can tear through the body like a storm, with vestiges affecting the body for months. In 2007, Mario Ancic, a Croat who had cracked the top 10 at the end of 2006, contracted the illness, sat out six months to recover and saw his world ranking plummet to No. 85.

Federer, 27, dropped only one spot, from No. 1 to No. 2, but his fall set off seismic shock waves in tennis because of his seeming invincibility the previous four years.

He left tennis for six weeks after losing to Novak Djokovic in the Australian Open, a tournament he played believing his general malaise was due to food poisoning. It was not until March that Federer found out his lingering fatigue was a function of much more than bad food, frequent travel or physical exertion.

Federer was still feeling the effects of the illness this summer. Traveling 12 time zones to New York after winning the gold medal in doubles for Switzerland in Beijing, Federer experienced the Olympic hangover that dominated the conversation during the first week of the Open.

Fatigue was cause for concern. “I was so tired after Beijing coming here, and then of course I’m a bit worried,” Federer said. He added, “Maybe I put it down as sickness when I still feel a little bit slow sometimes.”

There was no rest for the weary. Federer’s draw provided inviting targets for him to shoot for and ammunition in the form of revenge. One by one, he picked off players who had beaten him earlier in the year. ”

In the third round, he prevailed in four sets against Radek Stepanek, who had upset him in Rome; in the semifinals, he knocked off Djokovic in four sets. .”

Murray’s upset of Nadal in a semifinal, which was contested over two days because of Tropical Storm Hanna’s intrusion, afforded Federer one more chance to avenge an earlier loss. ”

Roger Federer owns a dazzling array of shots, a keen court sense and a winning disposition.

He’s also got a pretty good set of ears. And he could hear what the tennis world was saying about him: At 27, his reign at the top was over.

“I was aware of it,” he said.

Whatever, that version of the vulnerable Federer who was TAGS:Epstein Barr virus, Federer, kissing disease, Mononucleosis, Roger, Roger Federer treatment of mononucleosis