NEW YORK-- The curtain has gone up on the US Open's two-week run in New York today.

Third-seed Agnieszka Radwanska was the opening act, taking just 63 minutes to win her first round match. Fifth-seed Li Na took a minute longer for her encore.

The way-off Broadway production stars Serena Williams in her dual roles as top-seed and defending champ. Her credits include 16 major titles including four at the Open.

Williams steps into the spotlight as part of the night schedule against 2010 French Open winner Francesca Schiavone.

Venus Williams did her part in the sister act with a 6-1, 6-2 upset of 12th-seed Kirsten Flipkens.

The day 1 supporting cast includes second-seed Rafael Nadalwho seems to have overcome a season-long battle with injuries by going 10-0 in hard court matches heading into the tournament.

Nadal takes on American Ryan Harrison as part of the matinee. Former top five-player James Blake says he'll take his final bow at the US Open. He's retiring after the tournament.