Classic demolition job pleases Wozniacki

Caroline Wozniacki's imperious Auckland Classic form has shown no signs of abating, helping her crush Croatian second-round opponent Petra Martic 6-2 6-2 and book herself a quarter-final berth.

Fresh off Tuesday's straight-sets demolition of Madison Brengle, the Danish world No.3 again made easy work of her foe on Wednesday, winning within an hour.

At times, Wozniacki's ground-stroke play was breathtaking.

She repeatedly pulled winning shots out of the bag as she earned an early first-set break over Martic, and then secured another at 5-2 to win the set.

Croatian world No.90 Martic, who showed plenty of mettle to beat Czech prodigy Marketa Vondrousova in the first round, didn't give up.

She took an early break from Wozniacki and went ahead 2-0 in the second set, but soon found herself under a Wozniacki onslaught and relented.

Wozniacki broke three successive times to seal the match, and will face Sofia Kenin in the quarters after the American's win over Varvara Lepchenko.

Kenin won 6-4, 7-6 (8-6) earlier on Wednesday.

"A couple mistakes here and there but, all in all, I can be pretty happy with my performance - especially because she's an aggressive player and serves big, but I managed to serve well and get a lot of returns," Wozniacki told reporters.

"I'm building on my game all the time - I still have a little time before Melbourne (the Australian Open) so hopefully I can get some more matches here.

"I love to compete, to be out there and playing for something."

Wozniacki's solid Auckland form also comes with the upside of moving to No.2 on the WTA rankings, and a potential Australian Open second seeding.

The 27-year-old will usurp Garbine Muguruza as world No.2 next week after the Spaniard's Brisbane International exit and may still move to No.1, depending on incumbent Romanian top dog Simona Halep's results at the Shenzhen Open.

Earlier in the day, Czech third seed Barbora Strycova also qualified for the quarters, overcoming a second-set hiccup to down Swede Johanna Larsson.

Strycova emerged a 6-1, 6-7 (3-7), 6-2 victor.

Sachia Vickery also beat Veronica Cepede Royg, Su-Wei Hsieh trumped Ysaline Bonaventure and Polona Hercog outclassed Kirsten Flipkens in straight sets.