BEIJING (AFP) - Naomi Osaka showcased the ruthlessness that won her the US Open as the young Japanese sped into the China Open quarter-finals on Thursday (Oct 4).

The 20-year-old, who stunned Serena Williams to win her maiden Grand Slam last month, was devastating against 10th seed Julia Goerges of Germany, winning 6-1, 6-2 in 65 minutes.

Osaka, the eighth seed in Beijing, similarly thrashed unseeded American Danielle Collins 6-1, 6-0 in the previous round.

She will face either home hope Zhang Shuai or three-time Grand Slam champion Angelique Kerber of Germany in the last eight.

Osaka sprang a major upset when she defeated Williams in New York, in a final that was overshadowed by the American accusing the chair umpire of being "a thief" and "a liar".