Former world number one Victoria Azarenka appeared to have breathing difficulties Tuesday as she crashed out of the Australian Open in a straight-sets loss to Jessica Pegula.
The 12th seed needed two medical timeouts in the second set after looking distressed and flushed.
Azarenka, who endured a hard hotel quarantine on arrival in Melbourne, used an inhaler to curb apparent breathing problems but gamely fought on before succumbing 7-5, 6-4 in one hour and 39 minutes.
"It was tough for her, she wasn't well but I just focused on myself," said American Pegula, ranked 61.
Azarenka, the 2012 and 2013 Australian Open champion, had pulled out of the quarter-finals of the warm-up Grampians Trophy due to a lower-back injury.
She had only played one match since emerging from quarantine, where she was not allowed to leave her hotel room for 14 days.
Azarenka, 31, showed little rust early as she raced to a 5-2 lead before spiralling and dropping the next five games.
She then struggled physically to halt her resurgence on the tour.
Last year's US Open finalist ended 2020 playing some of her best tennis since becoming a mother in 2016, falling short to Naomi Osaka at Flushing Meadows.
Pegula will be out to dash local hopes in the second round when she faces former US Open champion Samantha Stosur or Destanee Aiava.