Aryna Sabalenka celebrated her ascent to the pinnacle of women's tennis by powering into the quarter-finals of the US Open on Monday with a straight sets win over Russian Daria Kasatkina.

Sabalenka, who is guaranteed of becoming the new world number one next week following Iga Swiatek's fourth round exit on Sunday, cruised into the last eight with a 6-1, 6-3 victory over the 13th seed.

The Belarusian will play China's Zheng Qinwen on Wednesday for a place in the last four.

Sabalenka, who lost in the semi-finals of last year's US Open, is targeting her second Grand Slam title of the season after winning the Australian Open in January.

The 25-year-old from Minsk said after her win she was delighted to have secured the No.1 ranking -- but admitted she would have preferred to have beaten Swiatek in the final in New York.

"Honestly I had no doubt she was going to make it to the final -- I really wanted to have this battle with her and decide everything on court," Sabalenka said of outgoing No.1 Swiatek. 

"I was sad she lost, but it means a lot to me. I've been pushing myself all this year to reach this goal. It's unbelievable, it's something crazy, I still can't believe it."

rcw/mw