(REUTERS) - World No. 1 Angelique Kerber crashed out of the Hong Kong Open in the quarter-finals on Friday (Oct 14), the German slumping to a shock 6-3, 6-1 defeat to Australia's Daria Gavrilova at Victoria Park.

Kerber, who also suffered a surprise loss to Elina Svitolina in the round of 16 at last week's China Open, committed six double-faults and struggled on serve as her 38th-ranked opponent secured victory in 1hr 14min.

Moscow-born Gavrilova fired five aces against the German as the 22-year-old continues her quest for a first WTA singles title, and she will next face either Kristina Mladenovic or Bethanie Mattek-Sands for a place in the final.

Her victory over Kerber, who surged to the top of the rankings after winning the Australian and US Open titles this year as well as reaching the Wimbledon final, was her first against the German Olympic silver medallist in six meetings.