'D***head': Nick Kyrgios' extraordinary apology over 'unacceptable' act

Nick Kyrgios knew he had to "cut the bulls***" as his on-court antics threatened to derail another Australian Open campaign.

The Australian No.2 was coasting to a routine second-round win over French veteran Gilles Simon on Thursday night on Melbourne Arena.

But as the finish line approached - up 4-2 with the break in the third set - the 23rd seed lost his way.

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Two straight double faults from Kyrgios handed Simon a lifeline, with the former world No.6 gratefully accepting to force a fourth set.

In the aftermath, the Aussie directed his fury toward his player's box, which included Davis Cup captain Lleyton Hewitt.

"Of all the things you could say on break point, 'stay tough'," he bellowed.

"That's what I get, every break point, 'stay tough' ... wow. So creative, so creative."

Nick Kyrgios offered an apology after the match. Image: Australian Open

But rather than let the blip become a full-blown meltdown, Kyrgios hit the reset button to bounce back and score a 6-2 6-4 4-6 7-5 victory.

"I just put my head down," Kyrgios said.

"I lost my way a little bit in the third set. I put my head down, I told myself 'just cut the bulls*** and just get to work'.

"I got the break at five-all. It was a good feeling to get through that."

The 24-year-old Canberra native admitted it was the type of match he might have thrown away six or 12 months ago, but stopped short of attributing the turnaround to new-found maturity.

"I was 13 in the world ... I was all right 12 months ago. But, yeah, possibly," he said.

"I did come back from two sets to love down on that court four years ago ... but it could have gone to a dark place and I brought it back and I somehow scraped the win."

Nick Kyrgios celebrates his victory over Gilles Simon. (Photo by DAVID GRAY/AFP via Getty Images)

Kyrgios apologises over ‘unacceptable’ actions

After the match, Kyrgios was keen to make amends and said he would not direct them on what support he wanted from them in future.

"I was being a bit of a d***head to them," he said.

"I apologised as soon as I went back into the locker room. They don't deserve that. They do a lot of things for me on and off the court.

"It's not acceptable from me."

Earlier, Spanish chair umpire Jaume Campistol handed Kyrgios a time violation as he served for the second set.

It drew a comical response, with Kyrgios imitating world No.1 Rafael Nadal's fidgety service motion to illustrate his point.

"That's part of my motion," he said post-match.

"I started my service motion. There wasn't any extracurricular activities I was doing before my serve to waste time.

"That's the ref's discretion whether I went over the clock or not. It really didn't matter too much."

Kyrgios joins John Millman and Alexei Popyrin in the last 32 as the only remaining Aussies the men's draw and will next meet 16th seed Karen Khachanov.

He has a fiery history in his only previous clash with the Russian, a three-set loss at the Cincinnati Masters last August in which he was later fined for verballing abusing a chair umpire.