Defending champion Coco Gauff continued her run of success at the ASB Classic on Thursday with a 6-3, 6-0 victory over fellow teenager Brenda Fruhvirtova to reach the quarterfinals.

Gauff, the No.1 seed from the United States, took 70 minutes to defeat Fruhvirtova, 16, in their first meeting on tour. The 19-year-old Gauff has now prevailed in her past seven matches at the ASB Classic.

"I thought that I played well," Gauff said on court after her win. "[Fruhvirtova] started off playing really well, and I was able to raise my level. I thought I served well and did better on the returns, and I think I played a great match today."

Back in the elite eight in Auckland, New Zealand, reigning US Open champion Gauff will next face No.8 seed Varvara Gracheva of France, who defeated Swiss qualifier Lulu Sun 6-3, 6-4 on Thursday. It will be Gauff's first meeting with the World No.42 Gracheva.

Fruhvirtova gave Gauff pause in the early stages, where she matched the speedy American stride for stride. The Czech’s exceptional court coverage led her to a love break for 2-1, and after dropping serve in the next game, Fruhvirtova had two more chances to reclaim the break for 3-2.

However, Gauff powered her way out of that jam to grab the 3-2 lead herself, and she took command in the set by firing a passing winner to break Fruhvirtova for 4-2. Gauff had to save one more break point when serving at 5-3, but the World No.3 held on to take the one-set lead.

In the second set, Gauff zipped to a quick 5-0 lead. The American stared down two break points when serving for the match, but she came up with stellar serves to notch her seventh straight game and wrap up the win.

Gauff finished the match with 21 winners to Fruhvirtova's seven, and the American successfully converted five of her six break points.

World No.117 Fruhvirtova, who went 7-0 in ITF Challenger finals last year and garnered her first tour-level win over Anna Blinkova in this week's opening round, was also undone on Thursday by 28 unforced errors.