Two-time Grand Slam champion Naomi Osaka says she still does not see herself as a "top player" despite preparing to defend her Australian Open title next week.

The 22-year-old, who won her first major at the US Open in 2018, is seeded third in Melbourne.

"It's funny, you guys tell me this top player thing and I never really see it like that," said Osaka.

The Japanese starts against unseeded Czech Marie Bouzkova on Monday.

Osaka's maiden Grand Slam victory in New York was the standout moment of her rapid rise in 2018.

She won her first WTA title at Indian Wells in March and, on the back of her US Open win, climbed into the world's top five after being ranked 72nd in January.

"I still feel like Indian Wells was two weeks ago, 2018 Indian Wells. It's really weird," said a smiling Osaka, who became the first player since American Jennifer Capriati in 2001 to follow her maiden Grand Slam win immediately with another triumph when she claimed last year's Australian Open in Melbourne.

But she was unable to match those heights during the rest of 2019, which she describes as the toughest year of her life as she struggled to cope with the expectation her previous results had created.

"I guess just before everything (the success), if I lost it wouldn't be an article. Now if I lose there's news. It was tough adjusting to that," she said.

"I think I'm definitely more relaxed now compared to the US Open.

"I learned a lot there, just in a way of handling my nerves and what to expect. I'm glad I was able to experience everything that I experienced.

"I think heading into this tournament, I'll be more prepared."

Wozniacki 'calm' as she prepares for final tournament

Denmark's former world number one Caroline Wozniacki is approaching the Australian Open "like any other tournament" as she prepares to bring a distinguished career to a close.

The 29-year-old, who won her first Grand Slam at the 2018 tournament in Melbourne, is retiring after the event, saying she wants to "achieve other things in life".

She was diagnosed with rheumatoid arthritis last year, which she says was not the reason behind her decision to retire, although she wants to "work on" the autoimmune disease which causes pain and inflammation in joints post-playing.

The world number 35 has also enrolled at Harvard Business School and says she has a "slam packed" diary over the next six months.

Her plans include going skiing with her family, a couple of "girls trips" and a belated honeymoon with her husband David, the former NBA basketball star who she married in June last year.

"I've done everything I could to prepare as well as I can for this tournament, then hope for the best," said Wozniacki, who is unseeded and plays American Kristie Ahn in the first round.

"So far I'm calm and just enjoying myself. I'm sure once the last ball is hit, it's going to be a bit emotional."