Aryna Sabalenka says she tried to "stop thinking" about her serve on Saturday and it worked well with the world number two's woeful double fault count improving as she stayed in contention at the Australian Open.

The Belarusian had tallied 31 double faults in two matches at Melbourne Park so far, and 70 from four matches this season, but only suffered 10 against Marketa Vondrousova on Margaret Court Arena.

It helped her beat the Czech 4-6, 6-3, 6-1 and ensure passage to the last 16 where she will meet unseeded Estonian veteran Kaia Kanepi who overpowered Australian wildcard Madison Inglis 2-6, 6-2, 6-0.

"I was just trying to not really focus on my serve. Just trying to forget about my serve, and that's was working today," said Sabalenka, a semi-finalist last year at both Wimbledon and the US Open.

"I think it's more mental, because I put a lot of pressure on myself about my serve, and the last matches I was trying to control everything on my serve -- my legs, my arm, the ball toss. And it was overthinking.

"I just stopped thinking. Like today, I was focusing only on the good jump and that's it."

Despite her serving yips, Sabalenka found a way to survive her opening two rounds against players ranked in triple digits thanks to her explosive all-court ability.

She brought that to the fore again against Vondrousova after early wobbles.

On a hot day with ice packs out at the changeovers, Vondrousova took a 5-3 lead in the first set and while Sabalenka only sent down four double faults she couldn't turn it around.

Sabalenka also lost the first set in her opening two rounds but found a way back and the 23-year-old responded with the same fighting spirit, immediately breaking the Czech to race 3-0 clear in the second.

She held firm, firing just three double faults, to seal the set and turned up the pressure on Vondrousova with an early break to move 3-1 clear in the third. Two more breaks enabled her to romp to victory

"Feels like I'm warming up in the first set and then I start playing," she said with a smile.

"I really want to win it in two sets, and I think that's why I'm getting so emotional in the first set, and that's why I'm over-trying and I'm missing a lot.

"And after the first set when you're losing, you're kind of, Okay, maybe I don't have to overhit it or to panic. So maybe that's why."