Roger Federer and Justin Henin played up to their no. 1 seedings today and Nikolay Davydenko was a sure thing, too, on the opening day of the U.S. Open.

The final Grand Slam event of the season began on a sparkling morning, and Federer was his usual sharp self.

Trying to become the first man in the Open era to take this title four straight times, the Swiss star got off to the right start — he won the coin toss to serve. He then held serve all match and beat qualifier Scoville Jenkins 6-3, 6-2, 6-4.

“Maybe other guys like five-setters in the first round. I like straight sets more,” Federer said. “It’s nice to be into the second round. It always feels like a bit of a relief.”

A Wimbledon junior champion, Donald Young, showed why he might someday be America’s next big hope in tennis and third-seeded Jelena Jankovic won in straight sets.

“When you win matches at any level it helps you win at the other level,” the 18-year-old Young said.

But no. 18 Marcos Baghdatis, the last player Andre Agassi beat as a pro at Flushing Meadows, was upset in the first round and a former French Open champ, Juan Carlos Ferrero, also made an early exit.

Sisters Venus and Serena Williams were to play evening matches at center court after a tribute to Althea Gibson. Fifty years ago she became the first black player to win the U.S. National Championships, which later became the Open.

Henin, bidding for her seventh Slam title, defeated Julia Goerges of Germany 6-0, 6-3 at a half-full Arthur Ashe Stadium. Despite making only 44% of her first serves and committing seven double-faults, the usually steady Belgian star won every game she served.

“I don’t have a lot of things to say about that match because there wasn’t a lot of rhythm,” she said. “I was concerned the last few days with my shoulder. It’s getting better, but still a little bit scary.”

Over on the grandstand court, Davydenko attracted his share of attention for something besides groundstrokes and Grand Slams. After the fourth-seeded Russian breezed past Jesse Levine 6-4, 6-0, 6-1, he faced questions about his name surfacing in a recent gambling investigation.

During a match in Poland this month, Davydenko lost to 87th-ranked Martin Vassallo Arguello, retiring because of injury in the deciding set. A British online gambling company voided all bets on the match after receiving about $7 million in wagers, 10 times the usual amount.

Davydenko, speaking in broken but understandable English, denied any involvement.

“I try to say every week, I don’t do anything like this,” he said. “I never did.”

Davydenko said he expected to talk to investigators — he wasn’t sure which ones — after the China Open next month.

“It’s pretty tough for me, somebody talking about gambling,” he said. “I don’t know how long I have more questions about it. Maybe all year.”

The U.S. Open hired a security firm run by Howard Safir, a former New York City police commissioner, to oversee the event and guard against gambling problems. An investigative team is on site.

On an outer court, Young won a Grand Slam match for the first time, defeating Chris Guccione of Australia 6-7 (2), 6-3, 6-2, 6-3.

Max Mirnyi of Belarus successfully used one of his instant-replay challenges to beat Baghdatis 6-3, 7-5, 3-6, 7-6 (6) and Feliciano Lopez downed Ferrero 6-3, 6-4, 6-4 in an all-Spanish matchup.

In other men’s matches, no. 9 Tomas Berdych of the Czech Republic beat Marc Gicquel of France 6-3, 7-6 (0), 6-2, no. 10 Tommy Haas of Germany downed Steve Darcis of Belgium 6-7 (5), 7-5, 6-3, 6-4 and no. 13 Richard Gasquet beat Sergio Roitman of Argentina 7-5, 6-1, 6-2.

Jankovic defeated Jarmila Gajdosova of Slovakia, 6-2, 7-6 (2), no. 10 Marion Bartoli of France downed Alexa Glatch 6-1, 6-1 and no. 15 Dinara Safina of Russia eliminated Catalina Castano of Colombia, 6-2, 6-3.

Vera Zvonareva also won, beating Alina Jidkova 6-0, 6-7 (5), 6-0 in an all-Russian matchup. The 27th-seeded Zvonareva is always good for a little on-court drama and she didn’t disappoint, directing a few sharp words at the ballboys and ballgirls after losing a couple tough points.