WUHAN, China - Defending Dongfeng Motor Wuhan Open champion Aryna Sabalenka was a point from her biggest win of the season. Her opponent, Mutua Madrid Open winner Kiki Bertens - whom she had never beaten in four previous attempts - had just double faulted to hand the Belarusian a second shot at victory.

GALLERY: High Five - Previous Wuhan winners from Kvitova to Sabalenka

Sabalenka stepped to the line and drew her arms up as if she was pulling an arrow back on the world's largest bow for the crucial second serve. Clocking in at 106 miles per hour, she launched the ball straight into the net.

"It's funny, isn't it?" Sabalenka asked the media in her post-match press conference. "We just gave each other, like, a present, to show each other that we are nice."

She let out an exasperated sigh to the sky, and as she put her head down, the Court 1 crowd could see the 21-year-old wasn't scowling, but smiling.

"All these smiles coming out because I'm not putting a lot of pressure on myself on the court."

It was that lack of pressure that let Sabalenka shake off losing a 5-1 lead in the second set, four match points, and a set point from Bertens before finally securing a spot in her first Premier 5 quarterfinal of the season, 6-1, 7-6(9).

"The tiger is back," she grinned. "I'm just playing freely, not afraid of anything and just going for shots.

"Every time before the match I can't wait to go out and to play, and I'm so happy to feel this again."

Sabalenka's infectious excitement and wild swings took her through a trimphant week in Wuhan last year, and has now won 15 straight sets in the Hubei province dating back to her second round against Elina Svitolina.

That feeling faded by the spring of 2019, and was soon replaced by a sense of dread.

"On the court, I was alone. I couldn't look at anybody else. It actually helped me to understand what happened this year. I had been trying to find excuses, like 'Dmitry, this is because of you, because of that, that, that.' Nothing was about the tennis."

- Aryna Sabalenka

"When I was going up the rankings, every match was really interesting for me to play. I wanted to find the way to beat each opponent.

"Earlier this season I had this feeling where I wanted to play, but I didn't want to have tough matches. I wanted to win it easily."

It took a week alone at the Zhengzhou Open - where Sabalenka traveled without longtime coach Dmitry Tursunov for the first full tournament in their 15-month collaboration - for her to ultimately to rediscover her focus.

"I was kind of thinking a lot," she recalled. "Like I was with myself all the time, nobody was behind me, all this stuff. On the court, I was alone. I couldn't look at anybody else. I was just was focusing on my game, focusing on myself, my thoughts.

"It actually helped me to understand what happened this year. I had been trying to find excuses, like 'Dmitry, this is because of you, because of that, that, that.' Nothing was about the tennis.

"I'm happy that just like few days alone I understand this big thing..."

She trails off and muses with a laugh, "Why they didn't send me alone to a tournament earlier this year? This is also their fault!"

Sabalenka has been well-primed for positive thinking thanks to her time on the doubles court. The court hardly seems big enough for Sabalenka in singles, and yet she shares it effortlessly with Elise Mertens, whose quiet encouragement has made its impact on the gregarious and often self-critical Belarusian.

"Every time when I win point with a weird bounce, weird touch, whatever is it, Elise tells me, 'Good enough.' I was like that during this match, 'Good enough!'"

Mertens and Sabalenka, who qualified for the Shiseido WTA Finals Shenzhen shortly after winning the US Open, returned to Court 1 not long after the latter's win over Bertens to reach the quarterfinals over Lyudmyla Kichenok and Desirae Krawczyk in straight sets.

"Doubles helps a lot. I'm really happy that I found a great partner, we can compete on this great level, can go far in tournaments. It helps to find this confidence and right balance on the court."

Standing between Sabalenka and a return to the Wuhan semifinals is 20-year-old Kazakh Elena Rybakina, who advanced after Wimbledon champion Simona Halep retired late in the first set of their third round clash.

"I think she has same feeling like me one year ago," she said wistfully. "Nothing to lose."

Still, she wouldn't trade her 2019 experience, and aims to channel it through another successful Asian Swing.

"I think I kind of need to go through all this stuff, to understand what tennis is actually about. I'm happy to had this experience. It's tough, but it's gave me a lot, I think."