BEIJING, Oct. 6 (Xinhua) -- World No. 1 Aryna Sabalenka was upset by Kazakhstan's Elena Rybakina 7-5, 6-2 in the quarterfinals of the China Open here on Friday.
The top-seeded Belarusian was haunted by service problems throughout the match, committing eight double faults against Rybakina's one, and was broken four times by the fifth seed.
