A tenacious Novak Djokovic survived a US Open late night fright battling back from two sets down to tame fellow Serb Laslo Djere 4-6 4-6 6-1 6-1 6-3, and move into the fourth round at Flushing Meadows.
On the ropes and reeling Djokovic, as he has done many times before, he snatched victory from the jaws of defeat in front a record crowd inside a breathless Arthur Ashe Stadium court.
It marked the 38th time Djokovic has won a five-setter and kept alive the 36-year-old's quest for a fourth US Open crown that would pull him level with Margaret Court's record haul of 24 Grand Slams.
Djokovic had looked imperious in his opening two matches surrendering only 11 games in blowout wins over Frenchman Alexandre Muller and Spaniard Bernabe Zapata Miralles but his 32nd seeded countryman proved a far tougher test.
The two Serbs had only clashed once before that in Belgrade last year but there were signs then that Djere was a danger, with the contest needing three sets and two tie-breaks before Djokovic claim the win.
Djere signalled to Djokovic he was in for more of the same on Friday when he broke the second-seed to start the match and then held his nerve the rest of set for an unexpected and well-earned 1-0 lead.
Facing one of the greatest players of all-time under the bright lights of tennis's biggest stage, a fearless Djere could not be rattled piling on the pressure with another break to go up 4-3 in the second on the way to a 2-0 lead that left Arthur Ashe Stadium stunned.
Djokovic was not without his opportunities, but did not capitalise on his chances until backed into a corner.
With the crowd still buzzing Djokovic came out for the third set with an urgency and energy missing in the opening two sets, breaking Djere at the first opportunity and again to go up 4-0 on the way to cutting the deficit to 2-1.
With cracks in Djere's game starting to appear, Djokovic continued to dial up the pressure breaking again to open the fourth set pulling a mighty fist pump from the 36-year-old.
But Djere was not done immediately breaking back, setting the stage for what was a marathon third game that saw Djokovic regain control with yet another break.
Moving in for the kill Djokovic swept the next six games to take the fourth set and a 2-0 lead in the decisive fifth that he would never surrender.
Czech qualifier Jakub Mensik did not hit many happy returns at the US Open as he was crushed by Taylor Fritz on his 18th birthday.
American hope Fritz, the ninth seed, played the ultimate party pooper and gave Mensik just three games in a 6-1 6-2 6-0 victory.
"I felt good. I kind of had a clear plan of what I wanted to do, how I wanted to play him," said Fritz, 25.
"I returned well. I was moving really well. Yep, I just played a solid match."
Incredibly, Fritz has dropped just 13 games in his three matches in New York so far. He will face 21-year-old Swiss sensation Dominic Stricker in round four.
The USA are waiting for a first home men's champion since Andy Roddick 20 years ago, but they already have four in the last 16 with Michael Mmoh potentially a fifth.
They will definitely have at least one quarter-finalist as Tommy Paul beat Spain's Alejandro Davidovich Fokina 6-1 6-0 3-6 6-3, and he will face Ben Shelton, who got past Aslan Karatsev of Russia 6-4 3-6 6-2 6-0.
Frances Tiafoe, the 10th seed, came from a set down to beat Frenchman Adrian Mannarino to set up a clash with Rinky Hijikata of Australia.
"When any of us see the others having good results, it's motivating," added Fritz. "I think they'd all say the same thing.
"But it's motivating. Because if one of us does something, the others not only want to do it too, they now believe that they can also do it because we think we're as good as each other. If he did this here, then why can't I?"
He continued: "I think it's kind of this progression that we've had for a while now, why we're at where we're at. Someone achieves something big, then someone else comes and wants to match him or one-up him, and it's the cycle that keeps going.
"We're all such good friends, it's motivating, for sure."
