A forearm injury has blighted the second half of 2019 for Kvitova, who failed to get beyond the first two rounds at Cincinnati or the US Open, but Wuhan has proved a happy hunting ground in the past and yielded titles in 2014 and 2016.

The 29-year-old was given a test by world No.52 Hercog but claimed a 7-6 (8-6) 6-3 triumph in more than an hour and 42 minutes, thereby setting up a third-round meeting with Sloane Stephens or Wang Yifang.

Defending champion Aryna Sabalenka continued her imperious form on the hard courts of Wuhan, thrashing Danielle Collins 6-1 6-0.

Collins knocked out compatriot Venus Williams in the opening round but was utterly blown away after an early hold of serve, losing in just 51 minutes and without mustering a single break point.

It was otherwise a bleak day for the seeded players, with Angelique Kerber falling to Monica Puig and Caroline Wozniacki beaten by Hsieh Su-wei.

No.11 seed Kerber lost an epic showdown with Puig 7-6 (7-5) 5-7 6-1 in a match that lasted just 13 minutes shy of three hours.

"I don't think I've practiced that long in a really long time," Puig, who faces Alison Riske in the next round, said. "She pushes me to the extra level. I just had to continue to fight and believe in myself."

Wozniacki was beaten for the second time in 2019 by Hsieh, who claimed a 6-7 (2-7) 6-1 6-2 win and will now meet Svetlana Kuznetsova.

Donna Vekic, seeded No.16, and No.14 seed Anastasija Sevastova were also beaten, both going down 4-6 6-3 6-3 to Ons Jabeur and Christina Mchale respectively.

Garbine Muguruza saw off Shuai Peng 6-3 6-2 in an impressive outing, while Sofia Kenin, Elise Mertens, Rebecca Peterson, Amanda Anisimova and Veronika Kudermetova also progressed.