Caroline Wozniacki bowed out of the Sydney International in a marathon second round that saw former world No 2 Svetlana Kuznetsova take victory in sweltering conditions.
After three hours and 47 minutes, the 85th ranked Russian forced the woefully out-of-form former No 1 Wozniacki to a 7-6 1-6 6-2 defeat, in highs of 41 degrees, with women's top seed Agnieszka Radwanska saying play should have been abandoned until the temperature dropped.
The world No 4, who was given a bye into the second round, played the opening match on centre court and claimed the heat, that has sparked raging bush fires in Australia, was affecting players even that early in the day.
Radwanska, who beat Kimiko Date-Krumm, said: "I think this is too hot to play tennis.
"Even for players, for ball kids, for the people sitting out there, I think it's just too hot.
"Today was one of the hottest day I (have) played for sure."
Former French Open champion Li Na, who followed Radwanska on to court, also claimed the heat was too much to handle, despite progressing to the next round.
"I was feeling, I don't know, just feeling like unbelievable. They say it was 40, but even on the tennis court even more," Li said.
"I mean, even didn't finish the match, just finish (the) first set (and) I was feeling my feet already burning."
Kuznetsova, who spent six months on the sidelines recovering from a knee injury, had asked for a wildcard for Sydney but was forced to play qualifiers and said this actually helped her build momentum ahead of Tuesday's win.
She said: "It was very weird to go and play quallies, but, you know, it just makes you stronger.
"(It) definitely was a little bit uncomfortable, but it made me stronger (and) this is what I really was looking for in Sydney, to get matches."
Kuznetsova, who will meet second-seeded German Angelique Kerber in the quarter-finals, said she was not taking the win over Wozniacki as a turning point in her rehabilitation.
"I just don't think about it when it's turning point and when it's not," she said. "I'm here. I'm doing the best I can. That's it. That's over here. Tomorrow is another day."