The world number one has not yet come close to dropping a set and was far too strong in all areas for Jessica Pegula, wrapping up a 6-2 6-0 victory in just 63 minutes.
“That was solid tonight,” said Barty, who next faces another American in Madison Keys. “I had a lot of fun out here, I was able to serve and find a lot of forehands in the centre of the court and I was happy to take the game on.”
Barty previously reached the last four two years ago, losing to eventual champion Sofia Kenin and is hopeful of going further this time.
“I’ve grown as a person, I’ve grown as a player,” said Barty. “I feel like I’m a more complete tennis player. I’m absolutely loving playing out here. It’s been a lot of fun so far and hopefully there’s a little bit more left.”
Keys’ surge back to the top of the game continued with a 6-3 6-2 victory over fourth seed Barbora Krejcikova.
The former top-10 star missed this tournament last year after catching Covid-19 and struggled all season but won a WTA Tour event in Adelaide before arriving in Melbourne and with her 11th win has already matched her 2021 tally.
The American has blasted her way through the draw and hit 27 winners against French Open champion Krejcikova.
Speaking on court, she said: “I think I’m going to cry. It means a lot. Last year was really hard. I did everything I could with my team to really reset this off-season. I’m really proud of myself and so thankful to my team and my friends and my family for helping me through what was a really tough year.”
It is Keys’ first grand slam semi-final since the US Open in 2018, with her best run seeing her reach the final in New York the previous year, losing to Sloane Stephens.
She said of her previous semi-finals: “I think you take the experience out of it. I know I’m going to feel nervous. I know I’m going to be excited. I know all of those feelings are going to be there. But it’s also a completely different situation, time and person, all of that.
“I honestly feel pretty neutral. I have gone into every match thinking I can absolutely win any match that I’m out on the court. I will say it’s been kind of nice to be the underdog for the first time in a long time.”
Krejcikova struggled physically and was unable to find her best form.
“Today it was the heat with some physical conditions that started to bother me after five games,” said the Czech. “From there on I just couldn’t put it together.
“I wanted to finish the match. I wanted to try to do my best. I wasn’t really able to do that. Still I think it’s a really good experience and I can learn a lot from it.”
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