Victoria Azarenka believes she is hitting top form at just the right time and thinks she has a good chance of winning the US Open, which starts on August 26.

The Belarusian accepts that world number one Serena Williams will once again be the woman to beat but is confident of upsetting the American in New York, after beating her in Sunday’s Cincinnati Open final.

Azarenka also stunned Williams in the Doha final six months ago, one of only four defeats the 31-year-old American has suffered in her last 81 matches.

The two women have won seven of the last nine Grand Slam titles and are seeded to meet each other again in the final at Flushing Meadows.

Reigning Australian Open champion Azarenka, +300 to win the US Open outright, said of Williams:  “Every time we play, I face a big challenge. She’s my biggest opponent, and that’s what I want to go through.

“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 will not be a favourite. She is No 1 in the world. She is a great champion, and she’s defending champion, so she’s going to be a favourite.”

Williams is -138 to win a fifth US Open crown, while British number one Laura Robson can be backed at +12500.