ESPN Tennis

NEW YORK -- This is why they play the games:

Olivier Rochus, who may or may not be 5-foot-5, 130 pounds, is often mistaken for a ball boy or a junior player. In four previous U.S. Open appearances, the No. 100-ranked player in the world had not won a single match. His opponent, Carlos Moya, is the 1998 French Open champion and ranked No. 4. But on Saturday, they were equals, elevating the raucous crowd filling Armstrong Stadium into near hysteria.

In the end, when Moya improbably double-faulted on match point, the shortest player in the men's draw was a 4-6, 6-4, 6-3, 6-7 (5), 7-5 winner.

"It was unbelievable," Rochus said. "For me, that was the biggest win in my career. The atmosphere right there was phenomenal for me. Yeah, that was the best match ever. Everything: My game, the crowd. I think I will never forget this match, that's for sure."

Moya handled defeat with dignity.

"To be honest, I think he deserved to win today. Tennis right now is very close. I mean, any player can beat one of the top players."

On the men's side, at least.

While only three of the top 16 women's seeds failed to reach the round of 16 -- No. 4 Anastasia Myskina, No. 7 Maria Sharapova and No. 13 Paola Suarez -- the men's draw is a mess. In a number of David vs. Goliath matchups, the underdog has gotten over the top.

Moya, at No. 3, is the highest seed to go out, but he has marquee company: No. 7 seed Juan Carlos Ferrero, a Grand Slam champion and U.S. Open finalist a year ago; No. 8 seed David Nalbandian, a semifinalist here in 2003; No. 10 seed Nicolas Massu, the reigning Olympic gold medalist in singles and doubles; No. 12 seed Sebastien Grosjean, a two-time Grand Slam semifinalist; No. 13 Marat Safin, the 2000 Open champion; No. 14 Fernando Gonzalez, who won Olympic gold and bronze; and No. 15 Paradorn Srichaphan, the No. 1 Asian player.

All of them lost to lower-ranked players. The bottom line? Half of the top men's seeds are gone, even before the second week starts. This opens things up for the favorites -- No. 1 Roger Federer, No. 2 Andy Roddick, No. 4 Lleyton Hewitt and No. 6 Andre Agassi.

Saturday's biggest surprise was the demise of Moya. In two previous matches, he had won all four sets against Rochus, including a victory just over two weeks ago in Athens. What was the difference?

"I think in the Olympics, the ball was faster," Moya said. "I could get more points with my serve. Also, my forehand was bouncing higher than here. The ball gets very big here. I couldn't use that."

Moya, a much more powerful player than the diminutive Belgian, had an 18-2 margin in aces. The downside was 61 unforced errors for Moya, compared to only 36 for Rochus.

Ultimately, it was Rochus' determination that prevailed in the three-hour, 38-minute match. He was down a break in each of the last three sets.

"In the fifth set, he broke me," Rochus said. "We were playing for three hours and a half. I just tell to myself, 'Just keep going, it' only one break. You never know. Just fight.' "

This he did, to the very end, when Moya's second serve found the net.

"I was shaking a little bit in that point," Moya said. "I cannot do anything now."

"I was so nervous," Rochus said. "Then when I saw the ball in the net, I couldn't believe it."

This has been the season of Rochus' 23-year-old life. He won the doubles title at Roland Garros with fellow Belgian Xavier Malisse, which gave the small country its first Grand Slam men's title in the Open Era. Then, he reached the round of 16 at Wimbledon, previously his best Slam singles effort.

"I came here without pressure. I lost first round last year, so I had nothing to lose. Yeah, happens in tennis sometimes. You don't know why you play good."

Greg Garber is a senior writer for ESPN.com.