MOSCOW, Russia – No.3 seed Belinda Bencic had to show all of her powers of resilience to dig deep and fight back from behind to overcome Polona Hercog in the second round of the Kremlin Cup, 1-6, 6-3, 6-4 in one hour 58 minutes.

Not only did the Swiss drop the opening set before fighting back, she trailed 3-0 in the decider before storming through to set up a quarterfinal encounter against Dayana Yastremska or Kirsten Flipkens.

It was a vital success of the WTA World No.10, who kept her prospects of qualifying for the Shiseido WTA Finals Shenzhen alive with the victory.

“She has a difficult game style for me. I don’t like it so much and I had a hard time adapting to it but I’m happy with my fighting spirit today,” she said.

“Everyone’s very tired now it’s the end of the season. It’s all about your mentality now. I’m trying to relax and play how I’ve played this season.”

Bencic, who had won the pair’s only previous meeting over three sets in Rome five years ago, was out of sorts at the beginning and was totally dominated in a first set that lasted 29 minutes.

The WTA World No.10 rallied in the second set but lost her bearings once again at the beginning of the decider. But with just a second career Top 10 win looming, Hercog stuttered, opening the door for her opponent as she slipped to 1-29 against players in this elite bracket.

It was a match that started ominously for the Slovenian as she was forced to produce a couple of impressive second serves to dig herself out of early trouble, having fallen behind 15-40 in the first game.

Having negotiated this perilous situation, however, a looping passing shot allowed her an instant break and set the foundation for a set that always looked like going in her favor thereafter.

Bencic came into the match struggling for form, having lost two of three first round matches since reaching the semifinals of the US Open. A lack of confidence was evident in her early play as she made uncharacteristic errors and finished the first set having made twice as many unforced errors as winners.

The Swiss had finished the opener on something of a high, halting a five-game slide before her opponent finally claimed it, and she started the second in far better voice, holding to love.

Indeed, she was a player transformed throughout the 46-minute duration of the second set, in which the level of tennis notably rose from both women. 

Bencic became increasingly aggressive, as she attacked the net with greater frequency, while Hercog countered with clutch serving and several cutting drops as she fought to save seven break points. 

With the pressure from Bencic now relentless, Hercog eventually buckled. She had been immaculate on the first six break points she faced, saving three with aces and another with a volley she adjusted to in a seemingly impossible manner, but as she sent a forehand long, it was all the invitation that her rival needed to draw level.

The beginning of the third set, however, was reminiscent of the first as Bencic once more struggled with her control and her emotions. Hercog established a 3-0 lead for the loss of just three points before the Dubai champion was able to respond, albeit with a great deal of help from her opponent, who served two double faults as she was broken.

It proved the watershed game in the match as Bencic would storm through and win six of the last seven games, reprising the strong form she had shown in the second and displaying her mental toughness in the face of adversity.