Serena Williams voiced concern over pollution from bushfire smoke at the Australian Open on Monday, saying that lung problems in the past could make her more vulnerable.
The 38-year-old American, who is pursuing a record-equalling 24th Grand Slam title, said it was a waiting game to see how conditions develop over the next fortnight.
The poor air that disrupted qualifying eased by Monday -- when Williams made a winning start against Anastasia Potapova -- and instead gave way to spells of heavy rain.
"I definitely was concerned, and am," said Williams, who suffered a lung blood clot during labour while giving birth to daughter Olympia in 2017 -- the second time she has needed emergency treatment for the problem.
"That (haze) is still a concern for, I think, pretty much everyone."
"I'm, like, 'Oh no, I'm already playing a little down than most people.'"