0:58 The great American became tearful during her post-match press conference before leaving the room
Williams gave the crowd inside the Rod Laver Arena a long wave goodbye with her hand on her heart, prompting questions about whether she would be coming back.
In her post-match press conference, the 39-year-old responded: “I don’t know. If I ever say farewell, I wouldn’t tell anyone. So…”
She then made an abrupt and emotional departure from the room after breaking down in tears.
“It was a big error day for me today,” she told reporters.
Asked if it was just a bad day at the office, Williams said: “I don’t know. I’m done,” before leaving the room in tears.
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Brady made her slam breakthrough with a run to the last four at the US Open last summer before losing to Osaka and has taken full advantage of a draw that opened up at Melbourne Park.
A 6-4 3-6 6-4 victory over first-time slam semi-finalist Muchova sets up a rematch with Osaka on Saturday.
Brady fell to the court at the winning moment, and said: “I can’t feel my legs. My legs are shaking, my heart is racing.
“I was feeling a little strange today. I was super excited but at the same time I was pretty flat-footed. I felt like I was stuck in mud. I didn’t really pick up my intensity until the beginning of the third set.
Brady and Osaka played one of the best matches of 2020 in the US Open semi-finals.
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