The first day of the US Open is always something special. On this day, right up until the first utterance of, “game, set, match,” every player has a chance. Today, there are 128 men and 128 women just seven matches shy of one of the game’s greatest glories—a US Open title. Players from more than 60 countries are entered into the singles draw of the 2009 US Open and on Day One, all start out equal. Of course, some are more equal than others.

Day One of the 2009 US Open features several players of the “more equal” variety. Six former US Open champions see action on this day, including both defending champs, Roger Federer and Serena Williams. Also logging court time today are Kim Clijsters, Venus Williams, Andy Roddick and Lleyton Hewitt. It’s the sort of all-star lineup that suggests a particularly grand opening.

Federer, who captured his record-smashing 15th Grand Slam singles title at Wimbledon in July, opens his quest for a sixth consecutive US Open crown against 18-year-old American wild card Devin Britton, runner-up at last year’s US Open junior boys’ event. This May, Britton, a freshman at the University of Mississippi, became the youngest man ever to win the NCAA Division I singles title, then reached the semis at the Wimbledon boys’ tournament. For the rising talent, getting a main-draw wild card into his country’s biggest event only to draw the greatest player of all time in round one is pretty much the definition of “good news, bad news.” The match will be a good opportunity for Britton to gauge his game, but the world No. 1 figures to take the NCAA champ to school. It’s Federer in three.

Serena Williams defends her title as the No. 2 seed, though she’s certainly been the top player at the Slams this year, winning both the Aussie Open and Wimbledon. Still, those two Slams are her only titles in 2009, and post-Wimbledon, she’s a mere 6-3 in matches, her best finish in three events a semifinal run in Toronto. She opens up against another American wild card, 19-year-old Alexa Glatch, who this year made a stellar debut as a member of the U.S. Fed Cup team, helping to lead that squad into the Fed Cup final. Glatch scored her biggest win as a pro at this year’s French Open, knocking off No. 14 seed Flavia Pennetta in the first round, but the seed she’ll face today figures to be a lot harder to plant. Both women are solid sluggers, but no one packs the punch of Williams. She’s through in two.

People are still talking about Roddick’s gutsy performance in the Wimbledon final, where he went the distance—and then some—with Federer. The 2003 US Open champ comes to Flushing looking to prove that he’s still got the goods for a second-Sunday showing on these hard courts, and the No. 5 seed certainly has the game to get there. Tonight, he faces Germany’s Bjorn Phau, whose best showings this year have been two semifinal appearances, including a run to the semis at the U.S. Clay Courts in Houston where he beat both Mardy Fish and Tommy Haas en route. This figures as the sort of match that Roddick can use to play himself into fighting form and in three, Phau is knocked out.

Clijsters, who won here in 2005, returned to the WTA Tour earlier this month after a two-year layoff during which she became a mom. Since her return, she’s made it abundantly clear that she still is very much a competitor and a force to be reckoned with—especially on hard courts. In two events, she’s 5-2, with six of her seven matches against top-20 opponents. She’s scored wins over 2007 Wimbledon finalist Marion Bartoli, two-time Slam champ Svetlana Kuznetsova and world No. 9 Victoria Azarenka in those two events. A wild card here, she could well prove to be the most dangerous floater since that iceberg that took out the Titanic. Her opponent, Ukraine’s Viktoriya Kutuzova, is a 21-year-old baseliner whose best showing this year is a semifinal appearance at the Strasbourg clay-court event in May. She’s not won a match in four hard-court events this year, and that’s not likely to change today. In straight sets, Clijsters is through to round two.

Venus Williams followed up her dazzling Wimbledon runner-up appearance with another run to the final of the Stanford, Calif., event, but then fizzled at hard-court tournaments in Cincinnati and Toronto, winning just one match at the two events. Still, much like her sister, Venus is a different player at the Slams, and the two-time US Open champ, owner of seven Grand Slam singles titles, always figures as a Flushing favorite. The No. 3 seed opens up against Russia’s Vera Dushevina, the 2002 Wimbledon girls’ champion, who earlier this month won her first career tour title at the hard-court Istanbul event. The Russian has twice made it as far as the third round here, in 2004 and 2007, but she’s completely overmatched here against Williams, who ought to use this match to re-establish herself on the hard stuff. Williams is through in an easy two.

Hewitt, the 2001 US Open champion and winner at Wimbledon the following year, has been steadily making his way back along the comeback trail this year after undergoing hip surgery last August. The former No. 1, whose game was always built on speed and a lethal ground game, has been finding his feet again, winning the U.S. Clay Courts title in Houston in April, reaching the quarters at Wimbledon, and making the quarters again in Cincinnati, where he beat big-serving Sam Querrey in the third round. The 28-year-old Aussie, playing here as the No. 31 seed, faces off against Brazil’s Thiago Alves, who this year reached his best-ever ranking of No. 88 on the strength of two final-round appearances at the ATP Tour Challenger level. Still, this match figures to be more of a challenge than the 27-year-old Alves can handle. It seems unlikely that Hewitt will go deep into this tournament—he’s slated for a third-round matchup with Federer—but he shouldn’t have much trouble with his opponent today. In three, Hewitt advances.