By sportswriters Spencer Musick and Michael Butterworth

WUHAN, Sept. 25 (Xinhua) -- Round two here at the 2018 Dongfeng Motor Wuhan Open brought more mixed results for local players and a number of major upsets.

The second round started in last night's late game, with China's Zhang Shuai taking out Slovenian lucky loser Polona Hercog 6-2, 7-5.

Zhang raced into a two-game lead out of the gate, breaking her opponent's first service game and surviving some strong returns from the Slovenian, who responded with a break of her own to make it 2-1.

But Zhang managed to gain momentum after that, breaking Hercog three more times on the way to taking the first set.

The second set was more of a contest, with Zhang winning her first service game before the Slovenian stormed into a three-set lead. Two double faults from Hercog allowed Zhang to take back control, breaking the Slovenian four times on the way to a straight-set win.

Tuesday's first match on Center Court saw Caroline Wozniacki dispatch Swedish qualifier Rebecca Peterson 6-4, 6-1.

Wozniacki fought hard from the outset, nearly breaking her opponent's first service before going on to serve out all but one of her games in the first set.

The second set was not much of a contest, with Wozniacki breaking the Swede three times to take the win with minimal fuss.

In a major upset, No. 6 seed Elina Svitolina of Ukraine was beaten 6-4, 2-6, 6-1 by Belarus' No. 20 seed Aryna Sabalenka.

The match got underway with both players serving out their games to 2-2, followed by a Svitolina break to put her one game ahead. But Sabalenka responded with two breaks of her own and some stellar shooting, firing three aces on the way to taking the first set.

Svitolina suffered from inconsistency on serve throughout the match, firing five aces but making seven double faults.

Other action on Center Court saw Germany's No. 3 seed Angelique Kerber defeat Madison Keys 6-0, 4-1 after the American retired injured.

Kerber now faces Australia's Ashleigh Barty, who defeated local hero Zheng Saisai 4-6, 6-1, 6-2 in a little over two hours.

Willed on by a partisan home crowd, Zhang twice broke Barty's serve on her way to winning the first set. However, the Shaanxi native couldn't maintain that momentum, allowing 2018 Wuhan Open runner-up Barty to take the following two sets with relative ease.

After a spot of rain, No. 5 seed Petra Kvitova got her Wuhan Open off to a winning start, beating Serbia's Aleksandra Krunic 6-3, 6-4.

"I'm very satisfied with how I played today," said Kvitova, who hit 13 aces during the course of the match. "My serve helped me a lot, and I was very pleased with that."

The Czech star's reward is a third round tie against Russia's Anastasia Pavlyuchenkova, who bested No. 12 seed Kiki Bertens of the Netherlands 6-4, 6-2.

Spain's Garbine Muguruza also secured safe passage to the third round, comprehensively defeating Switzerland's Viktorija Golubic 6-0, 6-1 in just one hour.

"I started playing at a very high level and I maintained that throughout the whole match. I felt like I was not giving her a lot of options, and I was finding the right shots, and it was a pretty good match," Muguruza told Xinhua after her victory.

There was joy for Chinese fans next on center court, as Wang Qiang shocked No. 8 seed Karolina Pliskova of the Czech Republic to win 6-1, 3-6, 6-3 in a little over two hours.

Neither player was particularly strong on serve, with no fewer than 15 service games being lost over the course of the three sets.

However, Pliskova was especially erratic, with 11 double faults to Wang's four. The Tianjin-born star now faces Russian-born Australian Daria Gavrilova in round three.

In a nail-biting tie on Court 1 that ebbed and flowed, fellow Chinese star Wang Xiyu put local fans' emotions well and truly through the wringer, agonizingly failing to convert four match points in a final set tie-break before ultimately giving best to Russia's Daria Kasatkina, with final scores of 1-6, 6-3, 7-6.

The first of the evening games saw another major upset, as No. 4 seed and defending Wuhan Open champion Caroline Garcia was knocked out by Czech qualifier Katerina Siniakova 3-6, 7-6, 7-6 in a marathon three-hour contest.

As in previous matches, the quality of service was not the highest, with both players being broken a combined total of 21 times over the course of the match, but Siniakova's eight aces to Garcia's three ultimately helped see her over the line. The Czech now faces a third round tie against Muguruza.

There was also a big shock in Tuesday's other late match, as No. 1 seed Simona Halep of Romania was knocked out in straight sets by Slovakia's Dominika Cibulkova. Halep seemed out of sorts in the first set, as Cibulkova took it 6-0 with ease.

The tournament favorite fought back in the second set to lead 4-2, but Cibulkova managed to break Halep three more times on her way to taking the second set 7-5, securing a famous victory and a third round tie against Kasatkina.

In the pick of the doubles action, Xu Yifan and Gabriela Dabrowski overcame Zheng and Gavrilova 6-0, 6-3 to seal a berth in the quarterfinals.