'Zap you': Top players wrestle with scorching Melbourne heat
Competitors, spectators and officials roasted on day seven at Melbourne Park, where play was suspended on outside courts in the afternoon because of the scorching weather.
Courts that have roofs closed them to fend off the baking sun.
Matches started earlier than usual in anticipation of the unforgiving weather, but there were already testing conditions in the morning.
The American sixth seed Jessica Pegula was among those first out for a scheduled 10:30 am start at Margaret Court Arena.
She blasted to a 6-3, 6-2 victory over unseeded Russian Oksana Selekhmeteva in 66 minutes and said she was glad to get out of there as soon as possible.
"Nice to be first out on court and not a super long match and didn't need to kill myself in the heat today," she said.
She was eager to avoid a three-set match as the temperatures soared.
"I definitely think it could kind of zap you pretty quick with how hot it could get," she said.
Temperatures were already well into their 30s by late morning, although defending champion Madison Keys said she was quite used to it.
Keys, who like Pegula and many of the other United States players, trains in Florida, said: "Training there definitely prepares you a lot for the hot weather."
Another American title contender, Amanda Anisimova, conducted her post-match on-court interview wrapped in an ice towel.
"Super-hot today," said the fourth seed, who beat compatriot Peyton Stearns in straight sets.
"The conditions were really tough out there today, so just happy to be through."
Anisimova said it was stressful trying to squeeze in everything possible to cool down in the changeovers.
"It's just important to keep fuelling and also staying calm, to not spend my energy on emotions and stuff like that," she said.
More heat to come
Anisimova, beaten finalist last year at Wimbledon and the US Open, said keeping hydrated the day before and on match day was crucial.
Ice baths were another way to combat the conditions, she said.
Men's champion Jannik Sinner started his third-round match against unseeded Eliot Spizzirri of the United States with the roof open at Rod Laver Arena.
The Italian second seed struggled physically in the heat, placing bags of ice on each thigh after games.
The tournament has a Heat Stress Scale of 1-5, with five the highest.
It hit five in the early afternoon, prompting a suspension of play on the outside courts.
Sinner's match was held up as the roof on Rod Laver Arena was shut.
American eighth seed Ben Shelton was relieved to play under the roof at Margaret Court Arena in his win over Monaco's Valentin Vacherot.
"I don't think I could have finished this match without the roof, I don't think anyone could," Shelton said.
"You all stay cool out there."
The good news is that Melbourne's notoriously fickle weather is set to change again on Sunday with forecast highs of 24C.
The bad news is that temperatures are set to ramp up once more during the tournament's second week, peaking at 43C on Tuesday.