NEW YORK - Roger Federer and Rafael Nadal played like champs, and former winners Lleyton Hewitt and Marat Safin advanced Wednesday during a hectic afternoon at the U.S. Open.

A day after rain prevented any matches from being completed for the first time since 1987, virtually the whole tennis world was on display at Flushing Meadows. Andre Agassi and Lindsay Davenport showed up, too, to practice. In all, 80 matches were on the schedule.

A year after bowing out in U.S. Open’s first round on the day he turned 23, Andy Roddick celebrated turning 24 on Wednesday by reaching the tournament’s third round.

The 2003 U.S. Open champion, seeded ninth this time, beat Kristian Pless of Denmark 6-3, 7-6 (3), 6-3. It was the day’s only second-round match.

“I hope I’m going to give you guys something better to cheer about this tournament,” Roddick told the crowd. “Going home in the first round is not fun, I know that.”

With thousands of fans milling around the plaza, the place was cooking. The scent of grilling hamburgers wafted over outer court No. 5 — many years ago, Goran Ivanisevic joked that he never liked to play there because the smell made him hungry.

The top-seeded Federer rebounded from a startling loss two weeks ago to overwhelm Wang Yeu-tzuoo 6-4, 6-1, 6-0. Aiming at his third straight Open title, Federer had won 55 straight matches on North American hard courts before Andy Murray beat him at the Cincinnati Masters.

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“I thought I was always in control, obviously,” Federer said after his victory. “I always said I prefer to be the favorite rather than the underdog. That’s worked out for me since I became No. 1.”

Known for his success on clay, the second-seeded Nadal had an easy time on the hard court. He won the first eight points and beat 1998 Open runner-up Mark Philippoussis 6-4, 6-4, 6-4 in the first round.

“The last two years, I didn’t play very good here, and I want to play good,” said Nadal, a two-time French Open champion who has never gotten past the third round at this tournament.

Philippoussis still has a big serve, and he used it to pound 19 aces, but Nadal broke him three times. Nadal limited himself to 10 unforced errors, 25 fewer than Philippoussis, and saved all four break points he faced.

Safin, the 2000 U.S. Open winner, defeated Robin Vik of the Czech Republic 6-1, 6-1, 3-6, 6-3.

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Safin has exhibited some bizarre behavior in the past — he once dropped his shorts after winning a point at the French Open — but won in rather routine fashion. He became the most animated when he called for an instant replay after his serve was ruled out.

The video board showed it was indeed out and Safin spread his arms wide while a fan yelled out, “Challenge the challenge!”

Through mid-afternoon, there had been a total of 15 challenges at the Open, resulting in four overturned calls. Safin seemed to think there should’ve been more.

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“I guess they have to improve a little bit to make sure that the calls are right,” he said. “I don’t think it’s 100 percent sure.”

The 15th-seeded Hewitt, the 2001 U.S. Open champion, beat Albert Montanes 7-5, 6-4, 6-3 and No. 4 David Nalbandian defeated Michael Berrer 4-6, 6-7 (2), 6-3, 7-5, 6-2.

Also advancing were No. 10 Fernando Gonzalez, No. 12 Tomas Berdych and No. 26 Olivier Rochus. Ryan Sweeting, a 19-year-old wild card from the United States, advanced when his opponent, 2004 French Open runner-up Guillermo Coria, quit during the first set with an injured right thigh.