BRISBANE, Australia (AFP) — Naomi Osaka said Wednesday she was "super disappointed" but just being on court was a "personal win" after her return to tennis at the Brisbane International was ended by defending champion Karolina Pliskova.

Pliskova, who won the tournament the last time it was held in 2020, bounced back from losing the first set to grind down the Japanese star 3-6, 7-6 (7/4), 6-4 in the second round.

World No. 2 Aryna Sabalenka, meanwhile, thumped Italian Lucia Bronzetti 6-3, 6-0 in a dominant display on Pat Rafter Arena.

"Even though it's super disappointing today, I know that if I keep training and if I keep putting in the work, then I'll eventually get to where I want to be," Osaka said.

"It's kind of tough because she has such a great serve — my breakpoints could have been better, but I think other than that, we both played really well."

"Even stepping on the court is a personal win because a couple of weeks ago I was even doubting if I could play with everyone," she added.

"So I guess these two matches that I've had kind of prove to me that I am doing okay, and the year is just going to get better for me."

The four-time Grand Slam champion had not played a tournament since September 2022, citing mental health concerns. She had a baby daughter in July before deciding to make a comeback.

After an impressive first-round win over Germany's Tamara Korpatsch, Osaka started strongly against the 39th-ranked Pliskova, breaking the Czech's opening service game.

Pliskova, a two-time Grand Slam finalist, tied but Osaka broke again to take a 4-2 lead then held on to bank the opening set.

The momentum began to shift in the second set as the tall Pliskova began to find the mark with her serve.

She won the second set tiebreak then got an early break in the third, holding on with ease to take the match in two hours and 13 minutes.