MELBOURNE: Veteran coach Craig Tyzzer said Ashleigh Barty's hot form after nearly a year out had surpassed his expectations, particularly after they were separated for six months because of the coronavirus pandemic.

Barty is on track to become the first Australian champion since Chris O'Neil in 1978 and will be hot favourite when she plays 25th seed Karolina Muchova in the quarter-finals on Wednesday.

Australian expectations are rising for Barty, who has won nine straight matches, including at last week's Yarra Valley Classic, after remaining home most of last year because of the pandemic.

After deciding to stay in relatively Covid-19 free Queensland, Barty's training was complicated after Melbourne-based Tyzzer was unable to fly in for six months due to closed state borders.

With face-to-face contact not possible, the Australian coach had to use his imagination.

"I was able to actually watch her sessions from Melbourne through the camera set-up they have in Brisbane (where Barty trains)," said Tyzzer, who has been Barty's full-time coach since 2016.

"I could hear what was going on and everything.

"I could contact her during those sessions and say, 'Work on this, try this.'"

Eventually, Tyzzer and Barty reunited and they ramped up preparations ahead of the Australian Open.

"It was an ideal opportunity (for Barty) to take a break after a long year in 2019, early 2020," he said.

"So she probably only hit three to four times a week.

"We started pre-season in October. It's probably the longest pre-season we've ever had."

But Tyzzer said the 2019 French Open champion's imperious form had even surprised him.

"It's probably better than I thought because... you just don't know," he said.

"To be where we're is fantastic."

While their focus is on 24-year-old Muchova, who upset 18th seed Elise Mertens in the fourth round, Tyzzer said Barty planned on playing a full schedule this year, including the postponed Tokyo Olympics, that might see her on the road until Christmas.

"Because of the quarantine arrangements here, we won't come back for a while," Tyzzer said of Australia's mandatory 14-day quarantine for incoming travellers.

"We're hoping that we'll set up some sort of base somewhere probably in Europe where we can at least switch off."

Tyzzer added: "She's pretty keen to play (at the Tokyo Games). We're hoping for her that goes ahead."