NEW YORK (REUTERS) - Karolina Pliskova put on a serving masterclass to defeat Mariam Bolkvadze 6-1 6-4 on Wednesday (Aug 28) and advance to the US Open third round.

The towering third-seeded Czech pounded nine aces and won 90 per cent of her first-serve points at Arthur Ashe Stadium, which had its retractable roof closed due to rain.

World number 202 Bolkvadze, who was playing only her second main-draw match at a Grand Slam, appeared to struggle with nerves in a one-sided opening set.

Pliskova fired a blistering backhand winner to convert her fourth break point opportunity in the second set and extinguish any hope of a comeback by the Georgian qualifier.

The 27-year-old, who is known for being a perfectionist, said she is learning to be kinder to herself.

"It can be tough because sometimes I don't want to miss anything, even when I make some good winners I just still find something... it was maybe not that clean," she told reporters.

"But with the years and with some experience, it makes me feel better about it and just let some things go, which I was not able to do before.

"So even if the shot is not perfect or if it's perfect, it's the past now. Just keep forgetting things and start over again on the next point. That's what is happening with me right now."

Former world number one Pliskova is still searching for her maiden Grand Slam title and the speedy US Open hard courts, where she reached the final in 2016, could provide her best opportunity.

Next up for Pliskova is a third-round clash with either Ons Jabeur of Tunisia or Aliaksandra Sasnovich of Belarus.