Canadian qualifier Frank Dancevic and a ball boy, who both fainted, were the most obvious victims of the searing heat when temperatures hit 41 degrees Celcius on day two of the Australian Open.
Dancevic collapsed during his first round match against France's Benoit Paire on the uncovered court six. He resumed after medical attention but unsurprisingly ending up losing 7-6 6-3 6-4.
The 29-year-old sat with a bag of ice on his head and had plenty more stuffed into a towel around his neck at chanegovers but he and Paire were completely drained by the end of the two hour, 12 minute contest.
Dancevic said conditions were plainly dangerous for the players.
"I think it's inhumane, I don't think it's fair to anybody, to the players, to the fans, to the sport, when you see players pulling out of matches, passing out," he told reporters.
"I've played five set matches all my life and being out there for a set and a half and passing out with heat-stroke, it's not normal.
"Having players with so many problems and complaining to the tournament that it's too hot to play, until somebody dies, they're just keep going on with it and putting matches on in this heat.
"I personally don't think it's fair and I know a lot of players don't thinks it's fair."
A ball boy had earlier required medical attention after collapsing during Milos Raonic's 7-6(2) 6-1 4-6 6-2 victory over Daniel Gimeno-Traver on the equally exposed court eight.
The tournament's "extreme heat" contingency plan was put in force for women's matches, allowing an extra 10-minute break between the second and third sets, but the sliding roofs on both Rod Laver Arena and Hisense Arena remained open.
Under a change to the rules for this year, the decision on whether to stop matches at the tournament is now at the discretion of tournament director Wayne McKewen.
Rather than use the raw Celcius readings to assess the heat, organisers prefer to use the Wet Bulb Global Temperature composite, which also gauges humidity and wind to identify the perceived conditions.
Although there will be concerns about player safety, most competitors followed the line that, although conditions were tough, it is the same for both players.
There was no particular groundswell of support for closing the roof on both main show courts, either, although defending champion Victoria Azarenka said she would not have been against it happening in her match against Johanna Larsson.
"I would love it, I think my opponent would also enjoy that. But it's fine," she said. "I think we're all in the same conditions."
Roger Federer, the 17-times Major champion, was firmly against closing the roof on Rod Laver Arena.
"I think it should always stay open, honestly. That's my opinion," he said after beating Australia James Duckworth 6-4 6-4 6-2.
He added of the heat: "It's just a mental thing ... If you can't deal with it, you throw in the towel."
Although it was unclear whether it was connected with the heat, China's Peng Shuai vomited on court during her 7-5 4-6 6-3 defeat to Japan's Kurumi Nara.
There were also minor snags caused by the heat with France's Jo-Wilfried Tsonga saying he struggled with his footing as his shoes softened and Caroline Wozniacki concerned about her water bottle.
"It was a little warm out there today," the Dane said after beating Lourdes Dominguez Lino 6-0 6-2.
"Every time in the changeovers, ice bags, ice towels, everything ... I put the bottle down on the court and it started melting a little bit underneath, the plastic, so you knew it was warm."