The world No.4 trailed a set and 4-1 before rallying to beat the crafty 28th seed 5-7 6-4 6-1 in the third round on Saturday.

"I'm happy with how I fought," the 21-year-old said.

"For me that's one of the biggest things I always thought I could improve. It sort of seems like before I would accept defeat in a way."

The Japanese superstar, who claimed a maiden grand slam at Flushing Meadows with a controversial win over Serena Williams, was frustrated by the slice and off-pace shots of Hsieh.

Osaka made 20 unforced errors in the first set, smashed a racquet and was staring down the barrel of a first-week exit after conceding an early break in the second.

But she clicked into gear reeling off 11 of the last 12 games to make the fourth round at Melbourne Park for the second straight year.

"I just felt like she was playing too good, and I had to wait," Osaka sad.

"For me, it's a bit difficult to do that because my patience isn't so great."

Osaka rose from world No.68 to No.5 in 2018, winning her maiden WTA title at Indian Wells before US Open success in September.

Little-known at the Open last year, Osaka could take the No.1 ranking if she wins her second major.

"I felt really nervous in the first round but after that I felt really good," she said.

"I think there is the most attention during grand slams. So definitely it makes me really happy. I try to sort of channel that in my tennis."

Osaka will meet 13th-seeded Latvian Anastasija Sevastova for a place in the quarter-finals, who she beat in the quarter-finals at Brisbane earlier this month.

The pair have met four times in two years, with honours split.

Australian Associated Press