BEIJING, China, Oct 3 (Reuters) - Three-times Grand Slam champion Elena Rybakina crashed out of the China Open with a shock 3-6 6-4 6-3 defeat by unseeded Alina Charaeva in the second round on Saturday, marking a disappointing start to her reign as world number one.
The 27-year-old was playing for the first time since defeating four-times major winner Aryna Sabalenka to capture the U.S. Open title last month.
Rybakina had skipped Kazakhstan's Billie Jean King Cup Finals campaign after what she described
as a physically demanding month.
Charaeva, a 24-year-old Russian-born Armenian ranked 118th in the world, etched her name into the record books by becoming the lowest-ranked competitor since the introduction of the WTA rankings in 1975 to rally from a set down to defeat the world's top ranked player.
Having weathered Rybakina's early charge, Charaeva converted five of eight break-point opportunities and won 76% of points behind her first serve. Rybakina struggled on serve, committing seven double faults in the two-hour, 11-minute contest at the WTA 1000 hardcourt event.
Charaeva will next meet Britain's Sonay Kartal.
In the men's draw, German top seed Alexander Zverev swept aside local hope Shang Juncheng 6-0 6-3 in the round of 16.
Fresh from his U.S. Open triumph and helping Team Europe win the Laver Cup, Zverev will next take on 24-times Grand Slam champion Novak Djokovic in Sunday's quarter-final.
The 39-year-old Serb boasts a perfect 31-0 record at the ATP 500 event and holds the tournament record with six China Open titles.
(Reporting by Pearl Josephine Nazare in Bengaluru; editing by Pritha Sarkar)
