Guangzhou, China, 19 September 2019 | Matt Trollope

Sam Stosur won through to the semifinals of the WTA Guangzhou Open with a gritty victory over Nina Stojanovic on Thursday.

The Australian completed a 6-2 7-6(1) victory after trailing 0-5, 15-40 in the second set, during which she saved an incredible six set points to prevail.

The win saw Stosur turn the tables on Stojanovic, who had eliminated her from the second round of the Nanchang tournament just one week ago.

Into her first semifinal of 2019, Stosur will face the winner of the match between doubles partner Zhang Shuai, the No.4 seed, or Swiss Viktorija Golubic.

Stosur’s win marks just the second time she has won three consecutive matches this season; the other occasion was in Eastbourne, where she came through qualifying and went on to reach the second round.

Yet it may well not have eventuated that way; Stojanovic looked destined to send the match into a third set, and with the Serb having won 10 of her past 11 matches in China, there was every chance her confidence would have carried her through the third.

Stosur admitted she was preparing herself for a third set when she found herself staring down multiple set points at 0-5.

“I wanted to try and hang in there and start to find my form again, and I was able to do that,” she said on court.

“Then obviously got closer and closer and closer, and then had the opportunity to close it out, which was fantastic.

“(It was) less humid (today). It’s been really exciting playing here in Guangzhou — I’m having a great time and really excited and looking forward to the semifinal.”

Stosur played the cleanest of first sets, winning it in 33 minutes after committing just three unforced errors while smacking seven winners and winning 85 per cent of her first-serve points.

Yet the wheels fell off in the second set, a combination of Stojanovic settling into the contest and Stosur’s level dipping sharply.

The Australian told coach Rennae Stubbs during a coaching timeout that she was tiring, no doubt a result of her sapping, two-and-a-half hour victory over Bernarda Pera 24 hours earlier in 34-degree heat and humidity.

Yet she tapped into her energy reserves, and suddenly, rediscovered the sting in her game.

Stojanovic, surprised by Stosur’s increased intensity as well as the fact the veteran was no longer gifting her cheap errors, suddenly started to miss herself. And then she tightened up.

After missing two set points in the sixth game and another in the eighth, Stojanovic watched as Stosur drew level from 0-5 to 5-5.

She snapped Stosur’s run with a hold for 6-5, and promptly moved ahead 0-40 when Stosur’s game again broke down in errors. But despite facing another three set points, Stosur would not fold, outlasting the Serb from the baseline and sending the set to a tiebreak.

Stosur had by this point won the mental battle. She confidently feathered a drop shot winner for a 2-0 lead and made the score 4-0 with a calm forehand passing shot winner.

She moved ahead 5-1 when Stojanovic wildly missed a forehand, and didn’t lose another point.

Stosur is projected to return to world No.103 in next week’s WTA rankings.