At the Kooyong Classic exhibition in Melbourne, former No. 1-ranked Maria Sharapova struggled in the heat and smoke and her match against Laura Siegemund was called off late in the second set. Siegemund won the first set in a tiebreaker but players and officials decided to stop play at 5-5 in the second.
"Both players are feeling the smoke so we are going to stop the match at this point," the umpire said.
At Melbourne Park, Slovenian Dalila Jakupovic was leading her first-round Australian Open qualifying match against Switzerland's Stefanie Voegele when she dropped to her knees with a coughing spell. Ranked 180th, Jakupovic was a set up and one point away from a tiebreaker in the second set when she experienced breathing difficulties and retired from the match.
Former Wimbledon semifinalist Eugenie Bouchard needed some medical assistance during her first qualifying match before beating You Xiaodi 4-6, 7-6 (4), 6-1.
Organizers said further decisions on match scheduling would be made using onsite data and in close consultation with its medical team, the Bureau of Meteorology, and scientists from the Environmental Protection Agency in Victoria state.
Melbourne started the day with hazardous air pollution as smoke from wildfires in Victoria's east and in southern New South Wales state drifted through.
The central business district, close to where Melbourne Park is located, recorded overnight hazardous levels of fine particles in the air and the EPA categorized the air quality as "very poor."
Firefighters in the region spent the night being called out to fire alarms triggered by the smoke haze.