GUANGZHOU, China - Bernarda Pera headlined the day’s biggest upset against No.4 seed Aleksandra Krunic to move into the first WTA semifinal of her career at the Guangzhou Open.

The 23-year-old American had to come back from a set down and outlast Krunic through a hard-fought two hours and 32 minutes to score the 4-6, 6-3, 6-4 victory.

“I think the match started off pretty well, I broke her in the first game. But I kind of lost my focus, lost my intensity a little bit, and lost the first set,” Pera explained after the match. “Then I was able to step up a little bit my game, and was able to get through.

“Aleksandra is a great player and the conditions are very tough here, so I’m happy to get through. I look forward to playing again tomorrow.”

After narrowly dropping the opening set to the tricky Krunic, Pera changed up her strategy in the second, adding more variety and approaching the net to throw off her opponent’s rhythm. The gambit worked, and Pera reeled off the last four games in a row to level the match.

Pera grew in confidence as the match wore on, despite being down a break two times in the final set. She battled back from a 3-1 deficit to reach 5-3 and hold two match points - reminiscent of her second-round victory over Viktoria Kuzmova, where she won the last five games in a row to notch a 6-2, 6-3 win.

But Krunic refused to fade, saving both match points and breaking back to extend her stay in the match. She couldn’t halt Pera’s momentum, and the American got right back on track, converting her fourth match point to seal her spot in the semifinals.

Pera, whose previous best result was a quarterfinal run at Charleston, will take on No.5 seed Yulia Putintseva in her first ever WTA semifinals.

The No.5 seed had a more straightforward path to the semifinals than her future opponent; up against Kateryna Kozlova, Putintseva edged through a tough opening set and cruised in the second, winning 6-4, 6-1 to set up the final four clash. Pera leads the pair’s head-to-head record, defeating Putintseva 7-6(6), 6-4 in the first round of the US Open just a few weeks ago.

Also in action, former Top 10 player Andrea Petkovic knocked out the No.7 seed Vera Lapko in straight sets, 6-2, 7-6(2) - she’ll take on No.3 seed Wang Qiang in the second semifinal after the Chinese player dismissed Fiona Ferro 6-4, 6-0.