But he had his collar down when play began in front of a jam-packed Grandstand arena that was described as "the biggest of the week" for that court.
From that point the Aussie renegade negotiated the match without much fanfare — almost.
Kyrgios had a smooth opening, taking the first set against France's Antoine Hoang 6-4 before breaking in the first and fifth games of the second set to take it 6-2.
The first minor hiccup didn't arrive until early in the third when Hoang — having been broken in the first game of the set — managed to break back to level it at 1-1.
Kyrgios immediately broke again but after taking a 4-1 lead found trouble on serve as Hoang fought back to 4-3.
FIREWORKS FINALLY ARRIVE
The fireworks the fans were waiting for finally arrived with Kyrgios serving in the ninth game of the third set when Hoang hit a shot that was called out but challenged after Kyrgios heard the chair umpire call game.
He fired up, questioning the umpire before refusing to talk to him and calling an official on the court to explain.
"You can say game and then challenge? Is that what you're telling me? He said game, he said the score," Kyrgios railed.
"He hit the ball out. He said game. The game's finished now."
The official allowed the challenge to stand but Kyrgios served it out with ease to hold for 5-3.
It's been a mixed day for the Aussie men at Flushing Meadows as Alexei Popyrin and Alex De Minaur both surged into the third round but Jordan Thompson bowed out and Thanasi Kokkinakis was forced to withdraw from his match against Rafael Nadal.
Kyrgios' straight forward progress to this point of the tournament has been in contrast to the ripples he's created off court.
The 24-year-old accused the governing body for men's tennis, the ATP, of being "pretty corrupt" after his first-round win against Steve Johnson when he was asked about his record $A167,000 fine in Cincinnati earlier this month.
Kyrgios backtracked, saying he was trying to highlight what he sees as a "double standard" in how he's treated by officials, but the ATP considered the comment a "major offence" and has launched an investigation.