When Millman barely held serve after a gruelling 20-minute game, the deafening roar could've brought the roof down.
That came during an unusual stoppage after four games of the second set when Millman was instructed to go off court to change his whole kit because he was sweating so much it was making the surface unsafe.
After losing in the semi-final against Kei Nishikori and Marin Cilic in 2014, Novak Djokovic and Roger Federer have gone one step further 12 months later, setting up their second US Open final meeting, the first in eight years.
Still in search of her first Grand Slam title, the 14th-seeded Keys reached her third semifinal in the past five majors by using her big-strike game built on serves and forehands to overpower No. 30 Carla Suarez Navarro of Spain 6-4, 6-3 at Flushing Meadows on Wednesday night.
Djokovic, now ranked at number 6, defeated our last remaining hope for an Australian victor 6-3, 6-4, 6-4 in 2 hours and 49 minutes.
With Millman making headlines in Australia for his stirring fourth-round triumph over Roger Federer, even Rupert and Lachlan Murdoch were on hand on Wednesday night to see what all the fuss was about.
For the men, the humidity means packing 10 or 11 shirts to keep up with the sweat and changing shoes on court, as Dominic Thiem did in his epic four-hour, 49-minute quarterfinal loss to Rafael Nadal. We were all sweating. "Just trying to find a way to hang in there". We've witnessed throughout our rivalries in 10, 15 years, there are periods and intervals where I win couple matches in a row, then they win couple matches in a row.
"I didn't feel I had the runs on the board coming into the US Open", Millman said.
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We want to show that we are up there with the best and want to be considered as one of the top ten nations in the world. They wanted to bounce back after their difficulties at the World Cup. "We expected a tough game against Germany ".
Widely considered the best returner in the game, Djokovic kept accumulating chances - and then failing to cash them in. For men's singles matches, the break would come between the third and fourth sets.
He had two game points for a 5-2 lead but a double fault and a backhand wide opened the door for Cilic, who stormed through, shouting "Got it!" when he secured the break to narrow the gap to 4-3.
Once again, however, the Australian was broken at 4-4, upon which Djokovic served out to love to complete his victory.
"I try to fight every point", said Nishikori, who boasts an impressive record in decisive sets.
Millman has spent the majority of his career battling in the backwaters of the game, struggling to make ends meet while playing lower level Challenger tournaments. I felt like I had a good bit of momentum there.
Brewer says that the amount of sand or other granular items can be adjusted to make a court faster.
It has been a weird US Open.
"It will be a very tough one". The victor will meet either Rafael Nadal or Juan Martin Del Potro in the ultimate showdown for the 2018 title.