There were some concerning scenes as Victoria Azarenka found breathing very difficult during her first-round match at the 2021 Australian Open.
Pegula held a slender 4-2 lead in the second set when her opponent trudged over to the side of the court, hunched over and in clear distress.
Azarenka, who lost to Naomi Osaka in the US Open final in an incredible comeback run last year, was clearly unable to continue before she was led off court for a medical evaluation.
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The two-time champion in Melbourne, in 2012 and 2013, eventually returned as Pegula was able to close out a 7-5 6-4 win, but the scenes were troubling nonetheless.
Eurosport expert Annabel Croft, on commentary at the time, reflected on Azarenka's struggles as she was taken away from the court.
"I don't think she's feeling well at all, her walk has got so slow. I don't think she is feeling well," Croft said.
She's breathing very heavily. I think she needs to go and sit down. I think she is feeling very faint, and it's not the first time we've seen this kind of thing in Australia.

'Worrying times' - Azarenka struggles to breathe on court

"She is walking very slowly to that medical timeout and it would be a miracle if they get her back to full energy levels. She has just blown herself out."
Thankfully, Azarenka was able to return, but Pegula will now progress at the 31-year-old's expense. She spoke about her unhappiness with the situation after the match.
"I truly don't understand that rule of why, when somebody is sick, injured or whatever, they have to give their medical reason out in the world," she said in her post-match press conference.
"I think that should be changed, unless players do want to talk about that, then they can. But it shouldn't be a mandatory requirement for people to talk about their health issues. Even legally, doctors should not release any information.
"In terms of that, I feel like that should be a bit of a light on a new and adjusted rule that should be in place."

Highlights: Pegula wins through as Azarenka struggles

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