Roger Federer has been denied a quarter-final berth as he crashed out of the fourth round of the US Open, beaten by unseeded John Millman on Monday night and the five-time US Open champion has blamed the humidity for his shock defeat.
Federer and Millman clashed under the roof on Arthur Ashe Stadium in New York in a tie which finally drew to a conclusion just after 1am local time (6am BST).
The world No. 2 struggled to cope with the sweltering conditions in the tightly-packed ground as Millman, ranked No 55 in the world, recovered from a set down to win 3-6, 7-5, 7-6, 7-6.
Federer believes his Australian opponent was more accustomed to the heat because of his residence in Brisbane.
US Open five-times champion, Roger Federer lost 3-6 7-5 7-6(7) 7-6(3) to unseeded John Millman of Australian
And Federer blamed the lack of air circulation for his poor performance, which came with 77 unforced errors.
“I just thought it was very hot tonight,” Federer said.
“Was just one of those nights where I guess I felt I couldn't get air.
“There was no circulation at all. I don't know, for some reason I just struggled in the conditions tonight.
“It's one of the first times it's happened to me.
“Yeah, it's uncomfortable. Clearly just keep on sweating more and more and more and more as the match goes on. You lose energy as it goes by.
John Millman thrilled by his win over Roger Federer
“But John was able to deal with it better. He maybe comes from one of the most humid places on earth, Brisbane.
“I knew I was in for a tough one. Maybe when you feel like that, as well, you start missing chances, and I had those. That was disappointing.
“But, look, at some point also I was just happy that the match was over, I guess.”
The Swiss also felt the courts were playing a lot slower this year, adding to his demise.
“When you feel like that, everything is off, so... But, look, I've trained in tougher conditions,” Federer added.
“I’ve played in the daytime, you know, at 120. Some days it's just not the day where the body can cope with it.
“I do believe since the roof is on that there is no air circulation in the stadium.