Barty broke the American in her first service game of the match and never looked back from that point onwards, cruising to a 6-2 6-0 win in an hour and three minutes.
Following her win, the Queensland native could not resist taking a shot at Melbourne, as she touched on how the warm conditions this year have helped her game.
“Melbourne, this isn’t Melbourne, this is Brisbane weather,” she told Jim Courier after the win.
“There’s been plenty of heat throughout the day. Night sessions at the Australian Open are really special, to still have a bit of heat on the court is brilliant and I’m able to use that with my game as well.
“I love playing here at night [but] I love playing at the Australian Open, it doesn’t matter what time.”
Barty built the win on the back of her impressive service game which saw her win 22 out of 27 points on her first serve, with Pegula seeing just one break point opportunity for the entire match.
However, as she has done all tournament, Barty cut her American opponent to shreds with what is fast becoming her best weapon – the sliced backhand.
The 25-year-old’s brilliant use of the stroke left Courier on awe while on commentary during Nine’s coverage of the match.
“Ash’s slice technique is arguably the best backhand slice technique in the world period,” he said during the second set.
“Men’s, women’s tennis, it doesn’t matter. It’s spectacular. Roger Federer, if you’re back in Switzerland [listening], yeah that’s right I said it buddy. She might be better than yours.
“I’m a fanboy on Ash’s backhand slice.”
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Barty also earned another slice of history in her win, with her two games lost, the equal-fewest games lost in a women’s quarterfinal since 1987.
Barty joined tennis icons Martina Hingis and Jennifer Capriati, as well as Simona Halep as the only players to have lost just two games in a women’s quarterfinal.
Next up for the hometown hero is a semi-final clash against American world No.51 Madison Keys.