Nadal, Federer, Williams sisters highlight first day at U.S. Open

Former champions Rafael Nadal and Roger Federer highlight the men's action on Monday to start play at the U.S. Open, while Serena and Venus Williams are among the women on the schedule at Flushing Meadows.

Nadal could be considered the favorite after winning consecutive hardcourt titles in Montreal and Cincinnati after his stunning first-round ouster at Wimbledon. He won the 2010 U.S. Open title and lost in the 2011 final to Novak Djokovic, but was absent last year because of a knee injury.

Seeded second this year, the Spaniard will play the third match Monday at Ashe Stadium against American Ryan Harrison.

Nadal is in the same quarter of the draw as a seventh-seeded Federer, who has struggled through most of 2013. The five-time Open champ has just one title this year and was a second-round loser at Wimbledon.

Federer's seed is his lowest at Flushing Meadows since 2002 and he will open this year's stay with the final match of the night at Ashe Stadium against Slovenia's Grega Zemlja.

Other top men on the schedule for Monday are fourth-seeded David Ferrer and eighth-seeded Richard Gasquet. Both will play at Armstrong Stadium -- Gasquet against American Michael Russell and Ferrer against Australia's Nick Kyrgios.

The Williams sisters will play separate matches at Ashe Stadium.

Venus, a two-time Open champ who is unseeded this year as she continues to battle health issues, will square off against Belgian 12th seed Kirsten Flipkens in the afternoon.

Serena, the top seed, defending champion and a four-time winner at the USTA National Tennis Center, opens the night session at Ashe against former French Open champ Francesca Schiavone.

Poland's Agnieszka Radwanska will open this year's tournament at Ashe Stadium. The third seed will start the day's festivities against Spain's Silvia Soler- Espinoza, while fifth-seeded Li Na of China opens play at Armstrong against Olga Govortsova of Belarus.

American Sloane Stephens, a semifinalist at the Australian Open and a quarterfinalist at Wimbledon, gets a show court opener at Armstrong. The 15th seed will play Luxembourg's Mandy Minella.

A total of 32 women's singles matches are on the schedule for Monday, while 22 men's singles matches are on the docket.