Melbourne (AFP) - Imperious Iga Swiatek swept into an Australian Open semi-final against Madison Keys on Wednesday while Jannik Sinner’s powers of recovery will be tested to the limit when he faces home hope Alex de Minaur.

Five-time Grand Slam champion Swiatek edged closer to a first Melbourne crown with a ruthless 6-1, 6-2 victory over American eighth seed Emma Navarro in gusty conditions on Rod Laver Arena.

The 23-year-old second seed is building up a head of steam in her title charge.

She has yet to drop a set and has given up only 14 games so far in her five matches – seven of those in her first-round clash against Katerina Siniakova.

“Madison is a great player and experienced so you never know,” Swiatek said of the American.

“It will be tricky, I will just be focused on myself. She has already played a good tournament here and we are well aware of how she can play.”

Keys stormed back from a set down to beat Ukraine’s Elina Svitolina 3-6, 6-3, 6-4 in their quarter-final.

The 19th seed moved into the last four at Melbourne Park for the third time, 10 years after her first.

Keys, who will be 30 next month, leads the WTA Tour with 12 wins this season and is now on a 10-match unbeaten streak after lifting the Adelaide title.

She had to show her resilience to fight back against 28th seed Svitolina.

“I felt like I kind of just had to start playing a little bit more aggressive and try to get to the net a little bit quicker,” said Keys, who battled past former Melbourne finalists Elena Rybakina and Danielle Collins on her way to the last eight.

Two-time defending champion and world number one Aryna Sabalenka plays Spain’s 11th seed Paula Badosa in the other semi-final.

Swiatek and Sabalenka are duelling over the top ranking.

If Sabalenka falls against Badosa on Thursday, the Pole will again rise to the top.

Should Swiatek and Sabalenka meet in the final, the winner would leave Australia with the number one crown to go with the Melbourne honours.

- ‘Why not?’ -

World number one and defending champion Sinner had dizzy spells in the scorching heat of the afternoon during his four-set win against Holger Rune on Monday.

The 23-year-old Italian has an evening match against De Minaur with temperatures dropping considerably on Day 11 of the first Grand Slam of the year.

De Minaur is looking to become the first Australian man to reach the semi-finals at his home Open since Lleyton Hewitt 20 years ago.

Awaiting in the last four will be either American 21st seed Ben Shelton or the unseeded Italian Lorenzo Sonego.

Sinner struggled in the muggy conditions against Rune, his hand visibly shaking and his heart rate taken in the third set before he left court for a medical timeout.

De Minaur has never beaten Sinner, losing all nine meetings, including in straight sets in the fourth round of the 2022 Australian Open.

“It’s going to be an incredibly tough match and I’m going to have to do something I haven’t done before,” said De Minaur, 25.

“But why not start here?”

Shelton ground down French veteran Gael Monfils to set up a quarter-final against Sonego, who ended teenage qualifier Learner Tien’s fairytale run.