Serena Williams and Novak Djokovic head the direct entry lists for this year's US Open. Williams will aim to break the record she currently shares with Steffi Graf for most Grand Slam titles in the Open era, while Djokovic will seek to reach his sixth final in the past seven years at Flushing Meadows. The fields announced by the US Tennis Association Wednesday include the top 98 members of this week's ATP rankings, and 101 of the top 103 in the WTA rankings. The two women missing: 2006 US Open champion Maria Sharapova, who is serving a doping ban that she is appealing, and two-time runner-up Victoria Azarenka, who recently announced she is pregnant. Williams has won six of her 22 major singles championships at the US Open, most recently in 2014. Last year, her bid for a calendar-year Grand Slam ended with a semifinal loss in New York against Roberta Vinci. Other past women's champions at Flushing Meadows who are on the direct entry list: Williams' sister Venus, Samantha Stosur and Svetlana Kuznetsova. Three women are using a special ranking to get into the field: Peng Shuai, Galina Voskoboeva and Vitalia Diatchenko. There are five past US Open champions in the men's field: Djokovic, Roger Federer, Andy Murray and Marin Cilic. Six men got into the field with a protected ranking: Julien Benneteau, Janko Tipsarevic, Brian Baker, Thanasi Kokkinakis, Dmitry Tursunov and Jerzy Janowicz. Juan Martin del Potro, the 2009 champion, is entered as an alternate, meaning his ranking is too low for direct entry and he would need a wild-card invitation to participate. Because of a series of operations on his left wrist, he hasn't competed at the US Open since 2013. Eight men and eight women will receive wild cards from the USTA, while 16 men and 16 women will get into the field via qualifying rounds in August. The main draw for the year's last Grand Slam tournament begins Aug. 29, with the women's singles final on Sept. 10, and the men's on Sept. 11.
