Costeen Hatzi says that she had very little knowledge of tennis when she first met Nick Kyrgios, with the Sydney native seen being given a crash-course in the sport during Netflix's new series, Break Point.

Kyrgios is the star of the first episode of Netflix's new docuseries, in which a camera crew follows the 27-year-old during his singles and doubles campaigns at the Australian Open last year.

Hatzi plays an integral role in the episode - The Maverick - at which point the pair had been dating for under three months. The 22-year-old admits on camera that she knew nothing about tennis when they first met.

'We've been together about two and a half months,' Hatzi says. 'We met online and we've been hanging out every day since.'

Hatzi also opened up on her relationship with Kyrgios, insisting that he is not as wild as he appears on court.

'He's not as crazy as everyone thinks he is. I never really watched a tennis game in my life so this is all new for me.' 

Prior to Kyrgios's first round match against Liam Broady, the Australian's manager, Daniel Horsfall, is seen explaining the scoring system to Hatzi.

'If you've never seen a tennis score before, it can be confusing,' he says. 'It's a five-set match, but in every set, six games make a set. So it's basically first to six.'

Kyrgios went onto enjoy his best year in tennis, reaching the Wimbledon final before losing out to Novak Djokovic, and recently said that Hatzi is his 'secret weapon'.

'None of this could have been done without her,' he said. 'It's been a very successful year, not only on the tennis court but just in general. I'm feeling really, really good about everything and just enjoying life.

'And meeting Costeen was probably my favourite moment, probably the best thing that's happened to me - and the year I've had as a highly motivated and highly pushed player, has been because of her. That's been my favourite experience.

'I just feel happier off the court, really just trying to be happy off the court - and that shows up on the court too.

'She's just the best thing ever and just makes me feel amazing, believes in my tennis and believes in me off the court too. We have such a good relationship.'

Asked if he felt she was the secret weapon of 'Team Kyrgios', he had no doubt. 'That's it, that's it,' he said.