By Rory Carroll
NEW YORK (Reuters) - Partly cloudy skies and a cool breeze did little to dampen the enthusiasm of fans packed into Flushing Meadows for the U.S. Open on Monday, where the sport's biggest names were set to embark on their quest to win the year's final Grand Slam.
World number one and defending champion Novak Djokovic and French Open champion Ash Barty will take the court in the morning before five-times winner Roger Federer closes the night session on Arthur Ashe.
The most anticipated match, however, was the first-round showdown between Serena Williams and Maria Sharapova, a pair of powerhouses who for years were the two most recognisable names in women's tennis.
Williams and Sharapova have never met at the U.S. Open before and although eighth seed Williams will be the favourite against the world number 87.
Williams holds a commanding 19-2 career record against Russian Sharapova but the 37-year-old American's fitness could be an issue.
Seeking a record-tying 24th career Grand Slam title, Williams forced to withdraw from the Rogers Cup final in Toronto due to back spasms and sat out the Cincinnati Open this month.
The U.S. Open runs from Aug. 26 to Sept. 8.
(Reporting by Rory Carroll, editing by Ed Osmond)