Tournament's top seed and current world's No. 5 Agnieszka Radwanska of Poland eased past Aleksandra Krunic of Serbia to reach the final 16, while second-seeded Petra Kvitova of Czech Republic, who is ranked No. 6, was forced to retire due to a gastrointestinal illness at the first round of the WTA Shenzhen Open on Tuesday.

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The Pole was the big winner at the end of 2015 when she triumphed at the WTA Finals in Singapore in November, and began the 2016 campaign in a positive fashion with a 6-4 6-3 victory over the Serbian Aleksandra Krunic, who ranks No.108 in the world.

Bad weather meant the majority of matches were played indoors, but that was no hindrance to the top seed Agnieszka Radwanska of Poland who reached her career high in singles ranking on July 9, 2012 being the world's No. 2, according to the International Tennis Federation.

"I feel like I played my last match in Singapore a week ago," Radwanska stated."It's always tough to come back to the match rhythm, but actually I was feeling really good and didn't have any problems," she added.

In the other matches, tournament's second seed and current world's No. 6 Petra Kvitova of the Czech Republic was forced to retire after losing the first set of her opening-round match 6-2 against the Chinese Zheng Saisai due to gastrointestinal illness.

The Czech tennis player, who hopes to be back and be able to compete in Sydney next week, stated: "I was very weak and dizzy and I felt like I was going to vomit. I couldn't really play though, I couldn't really move at all."

Sixth-seeded Eugenie Bouchard of Canada, who is currently ranked at No. 49, defeated Croatian Donna Vekic (No. 103) 6-4, 1-6, 7-5, while Chinese Wang Qiang (No. 110) outlasted No. 5 seed Johanna Konta of the United Kingdom, who is currently ranked as No. 48, by 6-3, 3-6, 6-3.

TagsPerta Kvitova