Nick Kyrgios has been slapped with a $US10,000 ($A14,500) fine for ugly behaviour in his first-round match at Wimbledon when he spat towards a spectator.

The latest in several big-money fines this season for the Australian came, ironically, on Thursday after he’d been on his best behaviour while producing one of his finest Wimbledon performances to knock out No.28 seed Filip Krajinovic and roar into the third round.

Kyrgios, though, may have been leniently treated compared to the heavy fines he received in the US earlier in the year for meltdowns in both Indian Wells and Miami.

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After an investigation, tournament officials imposed the punishment following Kyrgios’s admission that he had spat towards a spectator and called a line judge a “snitch” during an explosive win over Briton Paul Jubb.

Kyrgios had pleaded mitigating circumstances, telling the chair umpire that he’d ignored his pleas for an abusive spectator to be ejected.

The fine, despite being at least twice as severe as any other handed out to players over misdemeanours early at this year’s Wimbledon, didn’t compare with those on the US swing when his behaviour at the two big ATP tournaments cost him $US60,000 ($A87,000).

Earlier on Thursday, Kyrgios had been perfectly behaved and perfectly brilliant – but evidently still felt the need to find someone to berate after morphing from the ridiculous to the sublime.

He’d never looked a more complete nor more focused a player on the lawns of SW19 than he did in the trouncing of Krajinovic – and didn’t he want his critics to know it.

Kyrgios evidently felt this was a day when the sheer breathtaking brilliance of his tennis had quite muzzled his critics.

“I just wanted to prove to people that, like, I’m really good. I feel like I just don’t have the respect sometimes,” said this most complex of characters when he came to his press conference clearly armed with indignation at recent headlines.

“There was just nothing the media possibly could tell me I did wrong today. I just know that you can’t possibly ask me anything and stir anything up.

“And I love it because then you can’t write anything. What are you going to say? Nothing today. Dumbfounded all of you.

“It was just kind of a reminder to put you all back in your place.

“He (Krajinovic) made finals at Queen’s, top 30 in the world, seeded. It’s a gentle reminder …”

He reckoned he wasn’t bothered about any investigation into his behaviour, saying: “I just feel like I’m comfortable in my own skin. Some people, like, love to just tear me down. It’s just not possible anymore.

“I couldn’t care less if there is an investigation, to be brutally honest with you.

“I know what I bring to the sport. One of the most important people in the sport. Do you want to speak about that?

“Nothing to investigate there because it’s just factual.

“So, yeah, I’m extremely confident in myself. All the challenges I’ve overcome in my life. Proud to be up here and doing it my own way.

“Being able to produce tennis like that at Wimbledon, it’s a dream come true for any tennis player.”