Angelique Kerber loses to Daria Gavrilova in Hong Kong quarter-finals

Angelique Kerber replaced Serena Williams as world number one at this year's US Open

World number one Angelique Kerber was beaten in the quarter-finals of the Hong Kong Open by Australia's Daria Gavrilova.

The German, who went out of last week's China Open at the last-16 stage, lost 6-3 6-1 in an hour and 14 minutes against the world number 38.

Kerber, 28, struggled with her serve and hit six double faults.

Gavrilova, 22 and yet to win a WTA singles title, faces France's Kristina Mladenovic in Saturday's semi-finals.