The 71-ranked Badosa won the quarterfinals with 6-4.6-3 as unseeded and will face the 15th-seeded Russian Veronika Kudmertova in the semifinals.
The eleven highest seeded have already been eliminated.
Before the Australian Open Melbourne, the organizer and the local health authority applied extremely tough quarantine rules, which hit Badosa the hardest of all because covid infection was discovered, the only player who got it, after a week and she was moved under police escort to a special health hotel without windows with stricter surveillance.
"Was treated like a criminal"
- It's the worst thing I've been through during my career.
I was treated like a criminal, said Badosa, who was released just days before the tournament and was knocked out immediately after almost three weeks in the guarded room, which she was never allowed to leave.
The food was left on a tray outside the door.
There have been no major successes for Badosa after Australia but on the gray gravel in Charleston she has found the right one.
The victory over Barty was her first over a top-20 player.
- I'm still a little shocked.
I can hardly believe that it has happened.
When she hit the ball, it was like "What's really going on right now?"
says the 23-year-old according to AP.
Barty happy despite the loss
Barty won the major tournament in Miami last week and looked strong in his first two games on the gravel before it stopped already in the quarterfinals.
- It felt like I took too many chances but looking back on my last three weeks so I can only bring with me positive emotions, says Barty who is preparing for the French Open which was postponed a week due to the pandemic and is played in Paris between May 30 and June 13.
She won the tournament in 2019, her only Grand Slam title, but abstained from the tournament last autumn and stayed at home in Australia during the pandemic.