Elena Rybakina swept aside two-time champion Naomi Osaka to reach the quarter-finals of the US Open and close in on becoming world number one.

The Kazakh second seed overpowered 13th seed Osaka to win 6-1 6-4 on Louis Armstrong Stadium to set up a quarter-final against China's Zheng Qinwen.

Rybakina will become world number one for the first time if she wins her last-eight tie in New York - even if top-ranked Aryna Sabalenka goes on to defend her title.

Reigning Olympic champion Zheng came from 5-0 down in the first set of her fourth-round match to beat former champion Iga Swiatek.

"Of course I want it, I don't know anyone who won't want this," Rybakina said of the number one ranking.

"I tried to approach it the same way and do everything I can, and fight to the end of my next match.

"If I serve as well as I did today, I think I can do well. Let's hope it goes my way."

Rybakina, 27, dropped only four points in a near flawless performance on serve against four-time Grand Slam champion Osaka.

She faced the 28-year-old full of confidence, having not dropped a set in her opening three matches at the tournament, and took control of the contest in a dominant first set.

Reigning Australian Open champion Rybakina opened up a double break over Osaka, before sealing the set in just 21 minutes.

Osaka showed greater resistance early in the second set but, after failing to convert her only break point of the match, Rybakina soon seized control again.

She broke to go 4-3 up, before safely seeing out the rest of the match, with Osaka unable to contend with her opponent's deep groundstrokes.

Rybakina sealed the match inside 66 minutes with her seventh ace of a match where she hit a total of 29 winners to Osaka's nine.