He nearly fell over, spun around uncontrollably and even slipped on the sweat of his opponent before winning 6-3, 6-4, 6-4 against this year's ultimate underdog John Millman.
Withstanding energy-sapping weather, Djokovic ensures there's no upset as he annihilates Federer-conqueror to set up Nishikori clash.
But Djokovic composed himself to break again for 5-4 and this time made no mistake, moving through to the semi-finals for the 11th straight time he has competed here. He actually made more unforced errors (53) than Millman, but still never looked like losing. But we saw him a couple nights ago.
He adds that he can't recall any attempts to alter court speeds at Flushing Meadows with the intention of helping American players. He sat out past year because of an injured right elbow.
The structure was completed in 2016 so this year has been Djokovic's first proper taste of the changed conditions since then, and he was less than impressed.
John Millman, rear, exits to change his shoes he said were soaked from sweat, while opponent Novak Djokovic changes his shirt on court.
Play resumed after about a six-minute delay.
Keys punched her ticket with a victory over Carla Suarez Navarro on Wednesday.
There were other issues for Djokovic, as well, including in the third set when, ahead by a break, he was called by the chair umpire for allowing the 25-second serve clock - making its Grand Slam debut at this tournament - to run out on back-to-back points. "I'd play in a swimming pool if I got to play a quarter-final every week at a Grand Slam.That would be pretty fun". Keys said she will look to home support on Thursday when she resumes her rivalry with Osaka.
Millman, ranked 55th in the world, posted the biggest win of his career when he stunned five-time champion Roger Federer to reach the quarter-finals.
Osaka celebrated her win calmly and coolly unlike the floods of tears which greeted her last-16 victory over Aryna Sabalenka.
The Wimbledon champion has struggled in the unusually extreme conditions in NY this year and was again in discomfort during a 6-3 6-4 6-4 victory over Australian John Millman that lasted almost three hours.
Post Malone Involved in Car Accident
Flight trackers showed the plane circling over CT shortly after 1pm before making its way towards the NY airport just before 3pm. Malone was on his way to London Luton Airport in England, where the rapper was set to perform at the Reading & Leeds festival.
Millman said: "It was a tricky one coming off".
'When he's on, he's definitely a top-5, top-10 player.
Meanwhile, the women's draw at the 2018 US Open belongs to the lower seeds.
One player who wasn't sure what the fuss was all about was 20th-seeded Naomi Osaka, who represents Japan and trains in Florida.
If Djokovic wins in NY, he'll join Pete Sampras on 14 grand slam triumphs, a total only bettered by Roger Federer and Rafael Nadal.
It was first played at the U.S. Open in 2005, but did not have a match in Arthur Ashe Stadium until a year ago.
"There are so many people that stayed at the stadium and its past midnight".
Tsurenko didn't appear bothered by the conditions, but whether it was her health or just first-time jitters, she was off from the minute she stepped onto the court at Arthur Ashe Stadium. Djokovic held at love in game two and he moved in front on the third break point in game three when Federer sent a backhand long for the first break of the match.
Like Millman did to the 37-year-Federer, Djokovic finally wore down the 29-year-old Aussie. This will be Keys' second consecutive semifinal appearance at the US Open. He was able to come through on only four of his 20 break points.
There already was a rule on the women's tour offering that sort of pause between the second and third sets. U.S. Open officials began putting it in play last week, when temperatures first soared into the mid-90s.
But Nishikori broke Cilic in the final game, capturing the match with a blistering service return. Nishikori has won eight of the 14 meetings.