Serena Williams returns to Agnieszka Radwanska during her Rogers Cup semifinal victory on Aug 10 in Toronto. Geoff Robins / Agence France-Presse

Two of the star's four losses in past 14 months were to Belarussian

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 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 last Sunday at the WTA final in Cincinnati by a score of 2-6, 6-2, 7-6 (6).

"It's just always good to play such great players like Victoria who really plays well and makes me lift my game to a new level," Williams said.

Dominating pair

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

Williams beat Azarenka 6-2, 2-6, 7-5 in last year's US Open final but the effort in defeat resonates with Azarenka to this day.

"It will always be a special moment, for sure, because I felt like that whole tournament, that final match left a big mark on my future career," Azarenka said. "I still feel that way."

Williams sees no influence from prior meetings in a potential New York final with Azarenka again this year.

"It would be totally different circumstances," Williams said. "It's just a new event. You just got to go in there with a fresh mind."

Williams will go into the Open without a win streak such as she had the past few Grand Slam events.

"It makes me more relaxed and almost happy that I lost because now I don't have to worry about every day someone asking me about some silly winning streak," Williams said. "So maybe (losing in Cincinnati) was for the best."

Williams also finds herself in a cordial rivalry, appreciating Azarenka off the court as a friend and on the court as an adversary.

"She's so competitive on the court, like an animal, and I'm the same exact way, like my dad described me as a pit bull," Williams said.

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

Vulnerable in slams

But she has proven vulnerable in Grand Slams, falling to compatriot Sloane Stephens in the Australian Open quarter-finals and Germany's Sabine Lisicki in the fourth round at Wimbledon.

With Maria Sharapova pulling out due to injury, Poland's Agnieszka Radwanska became the third seed, followed in order by Italy's Sara Errani, China's Li Na, Denmark's Caroline Wozniacki and Czech Petra Kvitova.

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."

Azarenka took confidence from rallying to beat Williams in the Cincinnati final, but says the American will be the favorite on home soil.

"I will not be a favorite," Azarenka said. "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.

"About who's second favorite, third favorite, I don't really care about that. But I think it's a great boost of confidence."

(China Daily 08/26/2013 page22)