NANCHANG, China - The unseeded Nina Stojanovic posted the biggest upset of the Jiangxi Open so far, striking 21 winners to oust No.2 seed Wang Yafan 6-2 6-4 in one hour and 20 minutes in the first round.

The Serb has been in fine form of late, belying her World No.134 ranking. In both of her previous WTA main draw appearances this season, in Nurnberg and Jurmala, she has made the quarterfinals; in the final round of US Open qualifying, Stojanovic led Taylor Townsend by a set and 5-1 in the second set tiebreak before the American made a comeback - going on to upset Wimbledon champion Simona Halep and reach the fourth round. Undeterred by the missed opportunity, Stojanovic bounced back to take the title at last week's ITF W60 event in Changsha for the loss of just 18 games in five matches - and she came into today's match having beaten Wang in their only previous meeting, also on Chinese soil, 6-3, 6-4 in the 2016 ITF W50 event in Liuzhou.

"I started really focused with a big wish to win," smiled a delighted Stojanovic afterwards. "I think I'm in a good mood. Last week I won a tournament - even though it was on clay I had one day here to prepare and I was really believing in myself, I was brave.

"The weather was pretty similar but here it's more humid, and when you're playing on hard court it makes it feel even warmer - but I didn't have any trouble because I played in the shade on the Centre Court!"

All of these positives were on show as Stojanovic came out all guns blazing, overpowering the Chinese No.4 with a succession of finely struck forehands and confident drive volleys as she leapt to a 4-0 lead. A sprinkling of errors would lose the 23-year-old one of those breaks - but, piling pressure on Wang with no-holds-barred returning, Stojanovic bounced back to regain the advantage as the seeded player committed a third double fault to fall behind 5-2.

The second set reprised the first in many ways. Once again, Stojanovic dominated the opening stages with accurate power tennis, swatting winners away for fun and backing up her groundstrokes with smooth net play. And once again, the former World No.121 wobbled when up 4-1 with the double break: tentative and error-strewn play opened the door for Wang, who stormed back into the match by nailing a backhand pass.

Double faults would continue to haunt the Acapulco champion at the worst times, though: two more in the next game took her tally to five and handed her opponent a 5-2 lead. Stojanovic, still beset by double faults and errors, was unable to close out her seventh Top 100 victory at the first time of asking - but, bolstered by the insurance break, rediscovered her free-flowing power the second time around to seal her second match point with a third ace.

In the second round, Stojanovic will face 2011 US Open champion Samantha Stosur, now ranked World No.139, who came through an all-Australian derby 7-6(6), 6-3 over Arina Rodionova after saving a set point in the first set. Elsewhere, three seeds avoided the fate that had befallen Wang, with No.1 seed Zhang Shuai moving past Aleksandra Krunic 6-3, 6-3, Bucharest champion and No.4 seed Elena Rybakina overcoming Ankita Raina 6-2, 4-6, 6-3 and No.8 seed Kristyna Pliskova progressing with a 7-5, 6-3 defeat of Stefanie Voegele.

The home crowd had four local winners to cheer on: as well as Zhang, 2017 champion Peng Shuai dismissed Paula Badosa 6-4, 6-2, Zhu Lin defeated Thai qualifier Peangtarn Plipuech 6-2, 6-2 in one hour and one minute, and 17-year-old Wang Xinyu battled for two hours and 17 minutes before overcoming Chinese compatriot and wildcard Gao Xinyu 5-7, 6-0, 7-5.