| NEW YORK
NEW YORK Five former champions, including the reigning men's and women's title holders, will be in action at the U.S. Open on Tuesday, offering a tantalizing look at the past, present and possible future of the Flushing Meadows honor roll.
While Serbia's Novak Djokovic and Australia's Samantha Stosur are defending the titles they won for the first time last year, Maria Sharapova, Andy Roddick and Juan Martin del Potro are all looking to move closer to a second New York triumph.
For Roddick, who won his only grand slam title here in 2003, each match he plays carries added significance following his surprise announcement last week that he will retire after the tournament.
As the last American to win the U.S. Open men's single title, he has kept his emotions in check by riding a wave of patriotic support into the last 16.
"I'd be an idiot not to use the crowd right now. It's a huge advantage," he said. "Each match is almost like it's another memory."
Roddick's opponent on Tuesday is Del Potro, the towering Argentine who won the tournament in 2009 with a stunning upset over Roger Federer.
Del Potro has won three of his four previous meetings with Roddick but the 30-year-old American won their last clash, in Memphis last year.
"He's a tough matchup for anybody because he hits such a big ball," said Roddick. "I'm going to have to serve well, kind of try to rush him a little bit."
Djokovic has yet to drop a set at this year's U.S. Open and is an overwhelming favorite to win his fourth round clash with Switzerland's Stanislas Wawrinka.
For Stosur, a surprise winner here last year over Serena Williams, the challenge facing her is formidable as she is set to face world number one Victoria Azarenka of Belarus in the quarter-finals.
If their past meetings are anything to go by, the Australian will need to produce something special to keep alive her title defense. In their six previous matches spanning back to 2005, Azarenka has won the lot, all in straight sets.
"I have not done well against her in the past (but) I think there's a few things I've learnt over those last few matches," said Stosur. "A couple of times I've played pretty atrociously and a couple of times I thought I played not too bad."
Sharapova plays Marion Bartoli of France, a woman she has beaten each of the four times they have met before.
It has been six years since Sharapova won her only U.S. Open but the Russian has been in great form this season, winning the French Open to complete her collection of grand slam trophies.
"When you have moments of victory, when you're holding the trophy, you think back of the work you put in," she said.
"That's when you realize that it's worth it ... I still feel like I have a lot more left in me."
(Editing by Frank Pingue)