Naomi Osaka has never lost a Grand Slam after making the quarter-finals and if all goes to plan at the Australian Open she will be savouring a fourth major triumph before her 24th birthday.

The Japanese third seed reached the semi-finals with a clinical 6-2 6-2 win over Hsieh Su-wei on Tuesday, two years after suffering a big scare in an emotional rollercoaster of a match against the Taiwanese maverick at the 2019 tournament.

Osaka said her dominance in the rematch showed how much better she had become at sticking to a plan rather than relying on her instincts.

"I would say for me today it was really important to have a plan just because she's an opponent that I'm not really sure what's going to happen," Osaka said of the mercurial Hsieh, who beat her at Miami in 2019.

"So just having something to structure myself and not get carried away with what she's going to do was definitely really important.

"I feel like being able to receive information is something that I've been learning, and it's something that I feel my experience over these past couple years has helped me.

"Because, I think a couple years ago I probably wouldn't be able to understand what I was supposed to do that well here.

"But definitely I feel like I'm getting better at being able to stick to a plan. I know my attention isn't that great all the time, but yeah."

Osaka, who will play Serena Williams or Simona Halep in the semi-finals, could face world number one and home hero Ash Barty in a blockbuster decider if the Australian also survives.

Crowds are expected to return to the tournament on Thursday after a five-day lockdown due to a COVID-19 outbreak, and Osaka said she hoped Barty could have fans present for her bid to end Australia's 43-year wait for a home champion.

"Even for me, I've played the finals before with no crowd," said Osaka, who won her second U.S. Open title last year without fans at Flushing Meadows due to biosecurity protocols.

"It's definitely memorable. But I'm sure for her, if she reaches the finals and there's no crowd, it would be memorable but kind of in a sad way.

"I'm sure she would want a crowd. For me, I would want a crowd, too, even if they don't cheer for me. That's just the way life is. It's just more fun."