Dalila Jakupovic was forced to retire from Australian Open qualifiers because of the "unhealthy" air quality in Melbourne.
She collapsed with a coughing fit and was unable to finish her service game despite leading 6-4 5-6 against Switzerland's Stefanie Vogele.
"I was really scared," Slovenian Dalila Jakupovic told the media. "I never had breathing problems. I actually like heat. But ... I just couldn't breathe anymore and I just fell on the floor."
Former Wimbledon finalist Eugenie Bouchard and Australia's Bernard Tomic also required medical timeout during their games.
A thick haze from the raging wildfires has enveloped Melbourne, leaving air quality in the "very poor" to “hazardous” range.
Meanwhile, Australian Open said it will make further decisions about the matches after consulting with its medical team, the Bureau of Meteorology and scientists from the state’s Environment Protection Authority.
Top seed Jannik Sinner ensured Novak Djokovic will be absent from a Wimbledon men's singles final for the first time in eight years after handing the Serbian great a brutal Centre Court battering on Friday.
Fast bowlers Jasprit Bumrah and Jofra Archer took centre stage on the second day of the third test as India and England traded blows at Lord's on Friday and the match remained on a knife-edge.
Twice defending champion Carlos Alcaraz tamed the towering Taylor Fritz to reach his third straight Wimbledon final, rediscovering his A-game when it mattered most to battle past the American in a 6-4 5-7 6-3 7-6(6) victory on Friday.
Ireland's Ben Healy (EF Education-EasyPost) went out alone to win stage six of the Tour de France on Thursday, with Dutchman Mathieu van der Poel (Alpecin-Deceuninck) wrestling back the leader's yellow jersey from reigning champion Tadej Pogacar.