Kyrgios mostly keeps his cool to see off Hoang

Fiery Australian Nick Kyrgios mostly kept his cool en route to a 6-4, 6-2, 6-4 dismantling of Antoine Hoang in their second round clash at the US Open on Thursday.

The 28th seed had a row with the umpire even before the match started but avoided a full scale meltdown to reach the third round at Flushing Meadows for the fourth time.

Although his play was accompanied by the usual outbursts of temper, mostly aimed at himself, there was little wrong with his tennis as he set up a meeting with Russian Andrey Rublev in just under two hours.

Kyrgios, who is under investigation by the ATP Tour for critical comments he made about the organisation this week, won the opening coin toss and chose to receive.

It proved a smart decision as he broke the unseeded Frenchman in the first game and held serve at love in the next to race out to a 2-0 lead he would not relinquish.

He broke Hoang again early in the second and third sets to suck any drama out of the affair and keep his bid for a maiden Grand Slam title on track.

The only bright spot for the 23-year-old Hoang came in the third set, when he landed a deft backhand volley to break Kyrgios, who applauded his opponent.

But Kyrgios's 24 aces and punishing forehands proved too much for Hoang to handle and he went quietly into the warm New York night on the Grandstand court.

Before the match started, the combustible Kyrgios appeared to be up to his usual antics when he had the collar on his polo shirt popped up to reveal the words "Just Do You."

The chair umpire told him to put it down and Kyrgios demanded to know why, asking to speak to a supervisor and saying he would not play until he was shown the rule in writing.

After a brief conversation with a supervisor he backed down and the match began as scheduled.

Kyrgios had another minor tantrum in the third set when an ace appeared to give him a 5-3 lead.

The chair umpire said the word "game" but Hoang then challenged the call and the review showed that the serve was long.

Kyrgios loudly questioned why a challenge was permitted after the umpire had said the game was over and again asked to speak to a supervisor, who explained that the rules allow a challenge even after the umpire's call.

The row appeared to unsettle Kyrgios and he needed three match-points to finish off the contest.

The Australian is on a short leash with the ATP Tour after calling the organisation "corrupt" on Tuesday after it levied a record $113,000 fine for a slew of breaches during his second round loss at the Cincinnati Masters earlier this month.

On Wednesday he took to Twitter to say he regretted his choice of words. The ATP said it is looking into the matter.

Kyrgios, who at Wimbledon visited a pub on the eve of his third round defeat by Rafael Nadal, said he was trying to avoid temptation during his stay in the Big Apple.

"New York has a few distractions but I am trying to stay away from that," he said after the match.

"Obviously it's one of my favourite tournaments of the year and I really want to strap in and do well this week," he said.

"I am just trying to stay focussed."