Serena Williams kicks off her US Open defense on Monday, although the pick of the first round matches arguably involves her sister, Venus, who takes on No.12 seed Kirsten Flipkens.
WTA Staff

NEW YORK, NY, USA - First round action gets underway at Flushing Meadows on Monday, with several intriguing matches on offer, including a tricky opener for defending champion Serena Williams.

Monday, First Round

Arthur Ashe Stadium
[12] Kirsten Flipkens (BEL #14) vs. Venus Williams (USA #60)
series tied 1-1
A few weeks ago in Toronto, Venus Williams was involved in one of the more bizarre scorelines of the summer when she delivered a first set clinic before running out of gas and going down, 06 64 62, to Kirsten Flipkens. That was Williams' first match after recovering from a back injury and two tournaments further into her comeback a chance for revenge has presented itself.

Flipkens has been one of 2013's breakthrough performers, but has had her charge up the rankings temporarily halted by injury concerns of her own. A knee problem has limited the Belgian to just four matches since reaching the semifinals at Wimbledon at the start of July. Williams will need to serve well and attack early if she is to prevent Flipkens dominating behind her slice backhand and frequent forays to the net.

[1] Serena Williams (USA #1) vs. Francesca Schiavone (ITA #54)
Williams leads 5-2
Reigning champion Serena Williams kicks off Arthur Ashe's first night session against one of the few players on tour that can challenge her for major experience, Francesca Schiavone. Both players are appearing on one of tennis' four grandest stages for the 53rd time this fortnight and Williams is desperate to end it by being crowned US Open champion for a fifth time.

For the American, victory a week on Sunday would take her title haul for 2013 to a career-best nine and further consolidate her status as the woman to beat on tour. Before she can contemplate such an accomplishment she needs to make her way past Schiavone. Williams has already defeated Schiavone once this summer, en route to the Toronto title, and in the process extending her head-to-head advantage to 5-2.

[9] Jelena Jankovic (SRB #12) vs. Madison Keys (USA #39)
first meeting
While not quite in Serena Williams' league, Jelena Jankovic has certainly posted some encouraging numbers in 2013. The Serb, who began the year outside the Top 20, is seeded No.9 in New York and after a semifinal appearance on her last tour outing, in Cincinnati, will be quietly confident about her chances.

Jankovic was a runner-up here five years ago and must plot a tricky route if she is to make a second appearance. First up is Madison Keys, who possesses the game and temperament to spring an opening day surprise. If she is to do so, Keys, who withdrew from Cincinnati with shoulder tendinitis, will need to avoid extended baseline exchanges by serving well and taking the initiative early on in the rallies.

Around the grounds?
No.3 seed Agnieszka Radwanska kicks off her latest quest for a maiden major against Sílvia Soler-Espinosa, while other potential outsiders for the title in action include Li Na, Angelique Kerber and Sloane Stephens.