World No.1 Serena Williams enters the US Open as a heavy favorite to defend her title, but second-ranked Victoria ­Azarenka leads a host of rivals looking to dethrone her.

Williams is seeking her 17th Grand Slam singles crown and fifth US Open title, which would move her one shy of Chris Evert's Open-era record for most titles at the year's final major event on the Flushing Meadows hard courts.

"I'm definitely prepared. I'm ­definitely ready for New York," Williams said. "I definitely had more matches than I could want, but I'm definitely ­prepared for the US Open."

The 31-year-old American has been on an amazing run over the past 14 months, going 77-4 and capturing last year's Wimbledon, London Olympic Games and US Open titles, plus this year's French Open crown.

But two of those defeats came at the hands of Azarenka, in February's Doha final and at the WTA final in Cincinnati on Sunday by a score of 2-6, 6-2, 7-6 (8/6).

It was only the third victory for the 24-year-old from Belarus over Williams but with the two having won seven of the past nine Grand Slam titles, it sets the stage for a potential rematch of last year's US Open final.

Williams is looking for her ninth title of the year after triumphs at Brisbane, Miami, Charleston, Madrid, Rome, ­Roland Garros, Bastad and Toronto.

But she has proven vulnerable in Grand Slams, falling to compatriot Sloane Stephens in the Australian Open quarterfinals and Germany's Sabine ­Lisicki in the fourth round at ­Wimbledon, but completing her title run on Paris clay with a victory over ­Russia's Maria Sharapova.

Sharapova would have been the third seed at the US Open but she withdrew from the tournament on Wednesday, ­citing right shoulder bursitis.

As a result, Poland's Agnieszka ­Radwanska becomes the third seed, followed in order by Italy's Sara Errani, China's Li Na, Denmark's Caroline ­Wozniacki, Czech Petra Kvitova and ­Germany's Angelique Kerber.

Azarenka, the reigning Australian Open champion, says she has learned from past losses to Williams.

"Every time we play, I face a big ­challenge, my biggest opponent, and that's what I want to go through," ­Azarenka said.

"I had tough losses before against her, but I feel like I learned from those losses, and it helps me improve. I feel like I'm playing better and better. I'm reaching for the new level that I want to be at, physically, mentally, tennis-wise and that's the progression that I'm really the most excited about.

"I will not be a favorite. She is No.1 in the world. She is a great champion, and she's defending champion, so she's ­going to be a favorite."

AFP - Global Times