WUHAN, China — Caroline Wozniacki, Angelique Kerber and Anastasija Sevastova all lost to unseeded opponents in the first round of the Wuhan Open on Monday.
Two-time champion Petra Kvitova avoided an upset, though, beating Polona Hercog 7-6 (6), 6-3 in a second-round match.
The 13th-seeded Wozniacki lost to Su-Wei Hsieh of Taiwan 7-6 (2), 6-1, 6-2. Hsieh trailed 5-1 in the first set and attributed her slow start to having just arrived from another tournament in Japan.
"The first set was not easy, because I just came from Osaka," Hsieh said. "When I came on the court ... I was a little bit lost, and she was playing good as well. I asked my coach to come on the court and I said, 'OK, I don't feel anything. I feel weird.' And he said, 'It's OK, just try to play,' and I did. I tried to keep playing and after a couple of games, it was going better and better."
Hsieh broke Wozniacki's serve six times and saved eight of 10 break points. Wozniacki is 16-14 on the year.
Puerto Rico's Monica Puig defeated the 11th-seeded Kerber 7-6 (5), 5-7, 6-1 in almost three hours.
After failing to convert two match points and dropping the second set, Puig regained her form in the third to oust the three-time Grand Slam winner.
Puig now has a 3-3 lifetime record against Kerber, including a win in the final of the 2016 Rio de Janeiro Olympics.
"We've had so many great matches in the past," Puig said. "I have a lot of respect for her. I know it's not over until you go and shake her hand."
American Christina McHale ousted the 14th-seeded Sevastova 4-6, 6-3, 6-3 to advance to the round of 32.
Defending champion Aryna Sabalenka easily reached the third round, beating American Danielle Collins 6-1, 6-0 in the late match.
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