That was the first time in tournament history that the U.S. Open created an extreme heat policy for men's matches - they can opt for a 10-minute break between the third and fourth sets - similar to what's standard on the women's tour, when there can be a delay between the second and third sets. He's been a hero of mine.
Millman defeated the number two seed 3-6, 7-5, 7-6 (7), 7-6 (3) in a gruelling three-and-a-half hour match to reach his first ever quarter final in a Slam.
Djokovic, whose 3-3 record against Federer at Flushing Meadows includes victories over the Swiss great in the 2011 and 2015 finals, said he was relieved to get past 68th-ranked Sousa in straight sets as temperatures soared again. "Today he was definitely not at his best but I'll take it".
Kei Nishikori, runner-up in 2014, was also pleased to get through in three sets in blazing sunshine on Louis Armstrong Stadium.
Millman, ranked 55, could not be less like his compatriot Kyrgios. He cracked, double faulting again and making two more unforced errors, as Millman roared back to level the match at 1-1.
"I'm very happy to be through".
The 13-times grand slam victor had made easy work of the opening set, breaking Sousa twice, the second time to close out the set. He's got an aura about him. Until meeting Millman Tuesday, Federer hadn't dropped a set all tournament at the Arthur Ashe.
"So I have to see how that goes and if I have time, obviously I'll have a look, listen to your wonderful voice, Brad Gilbert courtside, and just enjoy the commentary".
"But I have never been a fan of playing to anyone's reputation".
Federer broke first on the way to a 5-3 lead in the set, but Millman won the last four games, breaking Federer twice.
Tsurenko left the court for a health check after the first set and often leaned on her racket between points, saying later she felt dizzy at the Grandstand court, which doesn't offer shade the way the tournament's two bigger arenas do.
But it's his father Ron, nicknamed "The Fox", who has become somewhat of a social media star, after getting lost on his way to watch his son play at the Wimbledon earlier this year.
Federer upped his game in a tight third set, and had the first chance to claim the set at 6-5 in the tiebreaker.
In the fourth set, he went up a break at 4-2, yelling "Come on!" and getting all of those rowdy spectators in their "RF" gear on their feet, prompting the chair umpire to repeatedly plead for silence.