(Photo credit: Robert Deutsch)

China's Qinwen Zheng needed nearly three hours Thursday to overcome countrywoman Han Shi 7-6 (6), 4-6, 6-2 in the opening round of the China Open in Beijing.

Zheng, playing on a wild card after her run to the U.S. Open quarterfinals last month, needed five set points to secure the opener before the 231st-ranked qualifier forced a deciding third set.

The former World No. 4 finally seized control in the third, breaking Shi twice to complete the victory in two hours, 44 minutes.

'I didn't change my rhythm like how I used to play, because I'm also trying to be more aggressive, so this caused more unusual mistakes,' Zheng said. 'I was more patient, was willing to change up my speed and rhythm and I was moving forward and backward. I was able to be more aggressive -- that was the key to this match.'

Zheng, currently ranked No. 54, improved to 6-1 against fellow Chinese players and will face 15th-seeded Anna Kalinskaya in the second round.

Spain's Paula Badosa also survived a marathon, rallying for a 4-6, 7-6 (7), 6-4 victory over Australia's Daria Kasatkina.

Kasatkina came within two points of closing out the match in the second set before Badosa escaped the tiebreaker and finished off her second victory over Kasatkina in as many months.

'It was also very emotional roller-coaster match because we were both wanting it so badly,' Badosa said. 'I saw at the end, she was struggling a bit, and I thought, this is my moment now. I'm happy that I got through it, especially mentally was a mental battle for me.'

Chinese wild card Xinran Sun made a successful WTA Tour debut when Germany's Eva Lys retired with a foot injury while trailing 6-1, 3-0.

The 16-year-old Sun, who won the U.S. Open junior title last month, rebounded from dropping her opening service game by winning nine straight games.

'Honestly, I feel good on the court,' Sun said. 'I'm just making my tactic and just following what I need to do.'

Another Chinese teenager, Yihan Qu, 17, pushed British qualifier Harriet Dart for more than three hours before falling 6-2, 6-7 (5), 7-5.

In a pair of all-American matchups, Ashlyn Krueger defeated former Australian Open champion Sofia Kenin 6-3, 6-3, and Katie Volynets topped qualifier Robin Montgomery 7-5, 7-5. China's Zhu Lin eliminated another American, Alycia Parks, 6-4, 6-2.

Elsewhere, Australia's Kimberly Birrell extended her winning streak to six matches by routing Japan's Aoi Ito 6-1, 6-1, while fellow Australian Storm Hunter beat Chinese wild card Yu Jun Lin 6-2, 6-1.

Camila Osorio of Colombia defeated Thailand's Lanlana Tararudee 6-3, 6-3, and the Czech Republic's Katerina Siniakova topped Poland's Magda Linette 6-4, 6-3.

Kamilla Rakhimova of Uzbekistan, Armenia's Alina Charaeva, Russia's Anastasia Zakharova, Sonay Kartal of Great Britain and China's Gao Xinyu also advanced.

--Field Level Media