Australian Open runner-up Marin Cilic says the decision to close the roof for the final influenced the outcome of the match, which he lost in five sets to Roger Federer on Sunday night.
Federer said he didn't know there was a heat rule in place to enable the roof to be closed for night matches at the Australian Open.
Cilic said the decision to close the roof made it much cooler than he expected and made it "very, very difficult" to adjust after practising outdoors all tournament.
Cilic fell short of saying the decision favoured Federer or cost him victory in the five-set match.
"It was difficult with conditions. Throughout the tournament I played all my matches outdoors, also preparing a hot day, 38 degrees. Then first match for the final to play with the roof closed, it's difficult," Cilic said.
"I have to say that decision, you know, could it have been different? I guess so. I think that it was just little bit difficult to adjust, especially the beginning of the match. With the roof closed, it was way, way cooler than I expected. That was very, very difficult, especially for the final to, you know, be in that kind of a situation."
Cilic said he was not asked if he wanted the roof closed but was consulted ahead of the decision. Both players were given the opportunity to practice indoors. Federer chose to accept the offer, Cilic did not.
"I didn't mind to have roof closed but it was a huge difference in temperature from having outside 38 then when you came in it was like 23, 24. I don't know. It was way cooler than I expected," Cilic said.
"I don't know (if it advantaged Federer). Just looking at my own side, I didn't feel those conditions before."
Federer said he was unaware the roof could be closed for heat in a night match.
"I wasn't sure if it was good for me or not, to play under the roof or not," he said.
"Of course, I backed myself in sort of indoor conditions. This is where my first success ever came ... usually when I play indoors, it's good for me.
"I didn't mind the heat, to be honest. I thought maybe for a bigger guy like Marin, maybe it's also going to slow him down faster throughout the match.
"I was surprised to hear they had the heat rule in place for a night match. I never heard that before.
"When I arrived to the courts, I was totally ready to play outdoors ??? for me, it doesn't change anything in the preparation, to be honest. I was ready for either."
The Australian Open remains an outdoor grand slam, but this one was won indoors.
The decision to close the roof was unconnected, organisers said, to reports by ESPN that Simona Halep had to be admitted to hospital for four hours overnight on Saturday for treatment for dehydration after her loss to Caroline Wozniacki in the women's final.
It was 38 degrees outside when Federer and Cilic walked on court. The roof was closed and air-conditioning turned on.
The decision to close the roof prompted criticism from, among others, Pat Cash, who questioned why it would be closed for reasons other than rain for the outdoor event.
Roof closed????? #ausopen isn't this an outdoor tournament? Fed must of been rubbing his hands together when he heard the news. #cilic needed some heat ,wind to upset Fed! https://t.co/XleC01JUwg pic.twitter.com/uoyBcWcczf??? Pat Cash (@TheRealPatCash) 28 January 2018
The decision was made by the chief medical officer and the tournament referee under the extreme-heat policy where the wet bulb reading exceeds 32.5 degrees.
