World number two, Victoria Azarenka, has been knocked out of the WTA China Open, quite surprisingly, by world number 43 Andrea Petkovic in Beijing's National Tennis Centre.
The defeat, which latest two hours and 22 minutes, means Azarenka faces no hope of defending her China Open title.
German Petkovic won 6-4 2-6 6-4, after losing seven straight games as Azarenka forced the decider. In the third set, Petkovic made a dramatic comeback, seizing the initiative.
Azarenka served 15 double faults, coupled with 44 unforced errors, while Petkovic took a medical time-out in the second set after complaining she felt unwell.
The result comes after a defeat against each of the Williams sisters this year - a second-round loss against Venus Williams in Tokyo last week, and just missing out in the US Open Final earlier this month against Serena Williams.
Speaking to the BBC, Azarenka blamed her health for her recent poor form. She said: "It was an awful match and very bad performance from me, so not much to say.
"It happens once, twice a year to every player, and happened to me today.
"If I'm going to be doing it again, I probably should have taken a longer break (between tournaments) and just prepared myself. I don't feel like I was ready to play.
"It's just my mistake for not paying much attention after the US Open how I managed my time and how I managed my health."
Other matches of the day saw China's Zhang Shuai defeat compatriot Peng Shuai 6-3 6-3 to set up a second-round match against tenth seed Roberta Vinci.
Italy's Sara Errani reached round three with a 6-3 6-2 win over Misaki Doi of Japan.
Serena Williams and Britain's Laura Robson play their second-round matches tomorrow; as well as Rafael Nadal and Novak Djokovic.
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