Nick Kyrgios' father Giorgos has lashed Wimbledon officials and accused them of double standards after a spiteful third-round clash between his son and Stefanos Tsitsipas that saw the latter smack a ball into the crowd in frustration.

The match, which Kyrgios won in four sets, was dramatic in every sense of the word and Kyrgios, Giorgos and many tennis pundits believed Tsitsipas should have been defaulted for hitting a ball into the crowd.

Tsitsipas was fined $10,000 (USD) for 'unsportsmanlike conduct', while Kyrgios copped a $4000 (USD) fine for an 'audible obscenity' - something he responded to on Twitter with a laughing face emoji.

Giorgos said if his son had hit the ball into the crowd like Tsitsipas, he 'would have been defaulted' and thrown out of the game.

'You've got to draw the line for everybody. I hate to see it for anyone. I feel sorry for all of them – the pressure is so much,' he told BBC Tennis podcast when asked whether there were double standards. 

He went on to say the four-set match was 'fantastic, unbelievable and good for tennis', and that his son is building very nicely as the tournament progresses.

'At times he plays as the best player on any surface, but it's a learning process, right?  Just got to keep ticking the right boxes and you get in the right places,' said Giorgos.

'It was a matter of time for him to settle, the nerves and stuff playing against a tough opponent like Stefanos is.. and while he was getting frustrated, he should have broken him a couple of times.' 

Kyrgios refused to play at one point during the game, as he appealed for Tsitsipas to be thrown out of the game for the dangerous act.   

'Is that a default or what? He just hit the ball at the f***ing crowd. Are you dumb?' Kyrgios could be heard directing at chair umpire Damien Dumusois.

'So you can hit a ball at the crowd, hit someone and not get defaulted? Give me all the supervisors. I'm not playing until we get to the bottom of it.'

Giorgos wasn't the only family member to spring to Nick's defence.

Brother Christos, who is not at Wimbledon due to welcoming his first child with wife Alicia Gowans, retweeted a video that showed Tsitsipas at the mercy of Kyrgios in a World Wrestling Entertainment (WWE) match, with assistance from Nick's Aussie best mate Thanasi Kokkinakis.

The video is from an infamous WWE fight between The Rock, Rikishi and billionaire Vince McMahon.

The Rock holds McMahon by the arms, and forces him to 'kiss the a**' of Rikishi, who is wearing just a sumo suit. 

In the tweet, Nick Kyrgios' head is imposed on Rikishi, with Kokkinakis holding Tsitsipas, forcing him to bow down and face Kyrgios/Rikishi's butt.

Christos also slammed Tsitsipas after the star called Kyrgios a 'bully' who has 'a very evil side to him'.  

'Lol in competition trash talk is bullying? Man… watch some football, basketball or literally any other sport in the world. Trash talk is common,' he wrote in reply to many tweets surrounding the comments. 

Many tennis players, pundits and fans agreed with the 'double standards' take, and believed Tsitsipas should have been thrown out of the match.  

'There's no doubt that Tsitsipas is extremely lucky. If that ball hits a spectator, certainly in the head, you're going to be disqualified,' said Tim Henman, who is on the All England Club's committee.

'He's lost the plot. Playing against Kyrgios, you've got to expect those antics. He'll get fined, but Tsitsipas is the one who's been distracted. He's the one who's lost.' 

Veteran tennis scribe Jon Wertheim agreed, calling the decision 'ridiculous' and referenced an incident at the 2020 US Open, where Novak Djokovic was default after a ball he smashed in frustration hit a line judge.

'My stance is simple: You rifle a ball recklessly in anger/frustration, you get defaulted - whether it hits someone or not. I'm fine with the Djokovic default, but Tsitsipas skates because he happened to miss hitting someone on the fly?' he wrote on Twitter.

Seven-time Grand Slam winner Mats Wilander, however, lashed both players for their antics, saying: 'I don't think this is what we want to promote in tennis.'

'Is it entertaining? Yes. Is it respectful? No. Is the tennis great at times? Unbelievable. I've never seen anything like it. I'm not sure I want to see something like that again to be honest,' he told Eurosport.

Kyrgios will now take on unseeded American Brandon Nakashima on centre court at approximately 10.30pm AEST on Monday night.

Should the star Aussie win, he'll progress to the quarter finals.

Fellow Australians Alex de Minaur, Jason Kubler and Ajla Tomljanovic are also in action on Monday night.