NEW YORK (Reuters) - Andre Agassi kicks off a busy day of action at the U.S. Open on Sunday with a third-round encounter with 25-year-old German qualifier Benjamin Becker.

Agassi, who has been receiving anti-inflammatory medication for his ailing back following a gruelling five-setter against Marcos Baghdatis on Thursday, plans to retire after the Open.

The 36-year-old Agassi's third-round contest tops the bill on a busy day of tennis following the washout of both sessions on Saturday.

The programme also features twice defending champion Roger Federer, world number two Rafael Nadal and 2003 winner Andy Roddick in action on the men's side.

Top-seeded Amelie Mauresmo, the Australian Open and Wimbledon champion, third seed Maria Sharapova and twice former champion Serena Williams return to competition among the women.

Fifth-seeded American James Blake plays Sunday's last match on the Arthur Ashe Stadium Court against former French Open winner Carlos Moya, while Federer will be next door at the Louis Armstrong Stadium facing unseeded American Vincent Spadea.