NEW YORK -- The United States Tennis Association threw a party Monday night.
There was a fabulous collection of former U.S. Open singles champions on hand for a celebration commemorating the 40th anniversary of the birth of the Open Era. Billie Jean King, Rod Laver, Ivan Lendl and Martina Navratilova, among many others, made appearances at Arthur Ashe Stadium. The tennis legends were joined by some present-day stars, including Venus and Serena Williams, Marat Safin and Roger Federer.
Which begs the question: Is Federer a present-day star -- or a past-tense tennis legend?
A year ago, after Federer won the U.S. Open for his 12th Grand Slam singles title, it appeared to be strictly a matter of when -- not if -- he would surpass Pete Sampras' record of 14 major championships.
Some so-called experts, citing Federer's ferocious four-year dominance -- he won three Grand Slams in three of the four previous years -- suggested he might equal Sampras at the 2008 U.S. Open. Some (who shall remain nameless) actually believed that this fortnight at the National Tennis Center might provide the ethereal No. 15.
This was supposed to be his coronation. But Federer is not the king in question; it is the newly crowned Rafael Nadal. Not only did he defeat Federer in the finals at Roland Garros and Wimbledon; the 22-year-old Spaniard also ended Federer's 4½-year reign as the world's No. 1 player.
Federer, who turned 27 earlier this month, has played in 14 tournaments this year and won only two minor events, in Estoril, Portugal and Halle, Germany. In four previous years, he averaged 10 titles. The man who lost only 15 matches from 2004-06 already has gone down a dozen times this season. Nadal is responsible for four of those losses, but eight other men, including Mardy Fish and Radek Stepanek, have beaten the once-invincible Federer. Since Wimbledon, he's fallen to Gilles Simon, Ivo Karlovic and, at the Beijing Olympics, to James Blake. That Blake was previously 0-for-8 against Federer underlines the issue of his diminishing returns.
With all due respect to Nadal, Federer's fragile state of mind -- and a game to match -- is the leading story line of this tournament. On Saturday, in his first comments here, Federer seemed to be looking for a little sympathy from the sprawling crowds.
"Maybe this year they will come out and support me and carry me through to another U.S. Open win," Federer said. "I think I need the support a little bit this year."
Is Federer playing possum, or does he really need a hug? Maybe a little bit of both. Federer plays his first match Tuesday night against Argentine Maximo Gonzalez, and it's the first time he's been the No. 2 seed in a Grand Slam since the 2004 Australian Open -- which he won, by the way.
Not surprisingly, Federer is spinning this as a positive thing.
"Five years, almost, I was expected to win every tournament I entered, except maybe toward the end a little bit on clay," Federer said. "So maybe now it changes a little bit, because obviously there's a shift in the rankings. Rafa will now feel what I had to feel for a very long time.
"So it will be interesting to see how he handles it. Maybe it's nice to go into a Grand Slam for a change maybe not having No. 1 next to me."
While Federer is 0-for-3 in Grand Slams this year, he was 17-1 against players not named Nadal. A semifinals loss to Novak Djokovic in Australia is his worst result, and he has a legitimate alibi. Mononucleosis -- which visited him after a long 2007 season that concluded with a series of three Far East exhibitions with Sampras -- left him depleted and, frankly, he hasn't looked quite right since.
"I know pretty much every player, except for one, that would take his bad year," observed Andy Roddick, the 2003 champion here. "So I think you have to use a little bit of perspective. He's created a bit of a monster for himself.
"But I think one big result and it's turned right around for him."
This is the hope that Federer loyalists cling to. Even factoring in the virus and the 20 days of practice Federer calculates he lost, it is impossible to know for certain if his Grand Slam run is over or if he just needs an offseason of extended rest. At some point, however, the backdrop of his historic track record will no longer allow people to suspend their disbelief regarding his current series of indifferent results.
In some minds, the U.S. Open may provide definitive evidence one way or another.
The blue DecoTurf II courts are fast and play better into Federer's game -- and, at the same time, work against Nadal's strengths. On the other hand, players report that this year's tennis balls seem bigger than those used last year, which would extend rallies, temper big serves and be an advantage for Nadal. Federer has won four straight titles here, but most oddsmakers list Nadal as the favorite, well ahead of Djokovic and Federer.
The widespread hysteria over Federer's sudden fall tends to obscure just how dominant he was for four years. Between 2004 and 2007 he won 11 of the 16 Grand Slams contested. Sampras' best effort over a four-year span was seven major titles. Even Steffi Graf -- who won 10 Grand Slams from 1993-96 and another nine from 1988-91 -- never equaled Federer's feat.
Federer's draw is exceptionally friendly; Fernando Verdasco (No. 13) is the highest seed he'd see in the quarterfinals, and No. 4 Nikolay Davydenko, who is in line for the semifinals, has lost to Federer there the last two years.
"Maybe I've been playing a little bit of catch-up all the way through the season," Federer said. "I think it's just a matter of winning a lot of matches in a row together, and I really feel like this is going to happen here at the U.S. Open if I play good.
"I hope to make it to the quarters or semis. I think then I have enough matches and enough confidence to go all the way."
Greg Garber is a senior writer for ESPN.com.