The Ukrainian sixth seed has never gone further than the quarter-finals at a grand slam but says she feels ready to set a new mark at this year's Australian Open.

Svitolina advanced to a final eight showdown with US Open champion Naomi Osaka after a see-saw battle with American Madison Keys on Monday at Margaret Court Arena.

The former world No.3 overcame blisters and a second-set hiccup to post a 6-2 1-6 6-1 victory.

The result mirrors last year's quarter-final appearance at Melbourne Park, when she lost to Belgian Elise Mertens, and keeps alive her hopes of supplanting Simona Halep as the world No.1.

A marathon 16-minute third game in the final set proved decisive with Svitolina surviving five break points before holding her serve and then running away with the win.

Up until then it appeared world No.17 Keys had the momentum after storming through the second set.

Svitolina said she knew if she could hold her serve she would have a good chance of breaking the erratic Keys in the next game.

"I knew that I had to be strong mentally and physically in that point, because the sun was very strong in that side, and I knew that I'm going to have a chance on the next game on her serve," she said.

Her premonition rang true with Keys serving a double fault en-route to the break.

The 24-year-old said that winning the title in Singapore in October against the world's best had boosted her self-belief.

"It gave me a huge boost of confidence, so I don't think about the past anymore," Svitolina said.

"I only look forward. I look for next challenge, and I try to win as many matches as I can, as many titles as I can, and this is the goal for the year."

Australian Associated Press