His Wimbledon reign and No. 1 ranking surrendered, Roger Federer has one trump left up his sleeve in his rivalry with Rafael Nadal: four straight US Open titles.
The Swiss tennis star believes that counts for something as he headed into the start of the year's final grand slam tournament on Monday.
"I still believe it's an advantage if you know how to win a US Open," said Federer, without a win so far this year on the game's biggest stages. "It's a tough tournament to win."
His first hurdle in his hunt for his 13th grand slam title will be Maximo Gonzalez, the world No. 114 from Argentina, on Tuesday morning.
Federer has owned Arthur Ashe Stadium at Flushing Meadows in recent years, winning the past four championships. He often treats the New York crowd to something special, be it a sharp black outfit or a behind-the-back, through-the-legs volley.
But his run towards Pete Sampras's record of 14 major titles has stalled this season, leaving him stuck on 12. Beaten by eventual champion Novak Djokovic in the semifinal of the Australian Open, Federer lost to Nadal in the final of the French Open and fell to his Spanish nemesis again in a thrilling five-set classic at Wimbledon.
At 27, Federer is no longer unbeatable. "You don't ever know when you're going to see the beginning of the end," said John McEnroe, who won the US Open four times between 1979 and 1984, after the Wimbledon match.
"When you lose a little bit of that swagger, guys in any sport pick up on that," he said. "You work for years to built that invincibility knowing that at some point it's going to break, the mirror is going to break."
Fluent in several languages, Federer understands what others are now saying about him.
"I've enjoyed it, talking about it, being compared with the greatest," he said. "It's a nice challenge ... beating the next generation, trying to play for a long time, trying to stay healthy, trying to beat records. It's always been difficult to beat all these guys. It's just not so easy to keep it up all the time. Eventually, sometimes they get you."
This year, more and more have done it – Andy Roddick, Andy Murray, Djokovic and James Blake among them.
"I think that's maybe what I feel most this year. You know, just losing too many matches," Federer said.
"I'm looking forward to the US Open. I still have really this and then the Masters Cup in Shanghai to really do well now. Try to save my season."
Questions were asked during media day on Saturday about a "different" Federer and whether Nadal was a clear favourite even though the Spaniard has never been past the quarterfinals in New York.
That's what happens when you've beaten your rival in two grand slam finals this year and won an Olympic gold medal that both players flew halfway around the world to pursue just two weeks before the Open.
American James Blake extinguished Federer's Olympic hopes in the quarterfinals in Beijing, beating the Swiss for the first time after winning just one set in eight previous matches.
Federer didn't seem too disappointed to hand the No. 1 mantle to Nadal, at least for now. Federer spent 237 weeks – four-and-a-half years – at No. 1 before Nadal replaced him on August 18.
"Rafa will now feel what I had to feel for a very long time," Federer said. "So it will be interesting to see how he handles it, but so far he's been great and he's played so well on all surfaces now. Maybe it's nice to go into a grand slam for a change not having No. 1 next to me – it should be interesting."
Andy Roddick, among the players to hand Federer one of his 12 losses this year, thinks Nadal deserves to be called the clear favourite at the US Open simply because he's "playing the best tennis".
But the American is not ready to give up on Federer, who is dangerously close to ending a five-year run with at least one grand slam title.
"I think it's tough to play perfectly for five years in a row," Roddick said.
"I think one big result and it's turned around for him. I know pretty much every player except for one that would take his bad year. So I think you have to use a little bit of perspective. He's created a monster for himself."
swissinfo with agencies
ATP Rankings (August 25):
1. Rafael Nadal, 6,700 points
2. Roger Federer, 5,930
3. Novak Djokovic, 5,105
The US Open is Federer's 12th grand slam title, two short of Pete Sampras's record.
He has won four times at Flushing Meadows, five times at Wimbledon and three titles at the Australian Open. But the French Open title still eludes him.
Grand slam titles (open era):
14: Pete Sampras
12: Roger Federer
11: Björn Borg
8: Andre Agassi, Jimmy Connors, Ivan Lendl
US Open facts
Surface: Hard court.
2007 Men's Singles Champion: Roger Federer
2007 Women's Singles Champion: Justine Henin of Belgium
Prize money: the men's and women's singles champions receive $1.5 million (SFr1.65 million) each.
Federer is not Switzerland's sole representative in New York. Tenth-seed Stanislas Wawrinka and Stéphane Bohli (ATP 133) will play in the men's draw and 15th-seed Patty Schnyder and Timea Bacsinszky (WTA 60) will play in the women's draw.
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