Naomi Osaka is through to her first quarter-final in six months after beating Julia Grabher in straight sets at the Auckland Open.

Osaka needed just under an hour and a half to see off the Austrian 7-5 6-3 to reach the last eight of a competition for the first time since 's-Hertogenbosch in June.

So far this season, the Japanese has not dropped a set, having also cruised past Lina Glushko in straight sets in the first round.

She had to overcome a brief rain delay on Wednesday but showed off some perfect serving, at 64%, while also saving both break points she faced on her way to clinching the first set.

"I've never played her before, so just getting into the groove of things is really difficult, especially because she doesn't have a traditional game style," Osaka told reporters.

"After the rain delay,y I was able to focus on the things I wanted to focus on a lot more, and I think that showed in the second set.

"I've said this for years, I'm not the most talented player, but I feel like I work the hardest and that gives me a lot of confidence. But when you get into a fistfight with another person, in the end, it's who wants it more.

"Last year it was really difficult for me to get that mindset, and you could see that in a lot of my matches. I think the tennis was there throughout the whole entire year, but it was more of a mindset thing. I think now, here, I think I'm ready for the battle."

Osaka is bidding to reach a first semi-final since returning to the tour last year after maternity leave and will face either Hailey Baptiste or Jodie Burrage for that spot.