The unseeded Australian John Millman's US Tennis Open odyssey is over following a sapping quarter-final loss to Serbian superstar Novak Djokovic.
Djokovic downed Millman 6-3 6-4 6-4 to reach his 11th semi-final in New York.
Millman won a stirring fourth-round triumph over Roger Federer but was unable to repeat the effort against Djokovic.
Just like Federer two nights earlier against Millman, Djokovic looked in distress as Millman toiled valiantly to turn the match into a physical endurance test.
But the 13-times major winner's class ultimately told, gaining a decisive break in each set to advance to a last-four meeting on Friday with rejuvenated 2014 runner-up Kei Nishikori.
Despite the straight-sets scoreline, Djokovic admitted he needed to dig deep to keep Millman at bay and eventually prevail after two hours and 49 minutes.
"I was struggling, he was struggling, we were all sweating," Djokovic said.
"I was just trying to hang in there and try to find a way to win the match.
"But definitely it was not easy conditions to play in."
"Full credit for John for putting up a great battle. He's truly a great fighter."
Millman indeed took the fight to the reigning Wimbledon champion in a showdown featuring the last two players to topple Federer this season.
Just as he did against Federer, Millman dropped the opening service game of the match to fall behind 3-0.
And as against Federer, that was enough to lose the first set after Djokovic benefited from a lucky net chord and then fought off a break point in the final game to serve the set out.
The lung-busting rallies were appearing to take their toll on Djokovic.
Upon missing a gimme volley - after Millman retrieved a lob with some incredibly scrambling - and then pushing a return wide, Djokovic staggered back into position before tipping water over his head at the changeover.
There was more drama three games later as Millman left the court "to change his attire due to the humid conditions".
The USTA later released a statement, saying he was allowed because the excessive sweat on the court could have proved hazardous.
After saving 11 of 12 break points, Millman wasn't able to fend off a 13th as Djokovic delivered a hammer blow to snatch the second set and leave Millman facing tennis's version of mission impossible.
Djokovic had won all 183 of his grand slam matches in which he'd enjoyed a two- sets-to-love lead.
But there was one final twist, the former world No.1 dropped serve for the only time after receiving successive shot-clock violations and then dragged a forehand wide to allow Millman to level up the third set.
But, not to be denied, Djokovic broke straight back to take the match to enhance his perfect semi-final record in New York to 11 from 11.