Kyrgios 'already a champion' in family's eyes, says brother

'For us, we've already got our baby brother back. Mum and Dad have got their son back.'

Wimbledon finalist Nick Kyrgios is one match away from a first Grand Slam title but his brother, Christos, said on Sunday the Australian is already a champion in his family's eyes after winning an off-court battle with his inner demons.

Kyrgios, who in recent years had become well known for his antics and outbursts, opened up on his mental health struggles in February, saying he had had suicidal thoughts in the past.

"For a big chunk of the last six or seven years, I lost my little brother," Christos wrote in a column for the Sydney Morning Herald.

"The world changed him. Tennis changed him. He became distracted, always worried about something.

"People wouldn't know this but Nick and I stopped talking for quite a while. He was so unhappy in himself that he shut out the people that had his best interests at heart."

Christos added that he had "got his baby brother back" and credited Nick's girlfriend, Costeen Hatzi, for helping turn his brother's life around.

"Since he met his girlfriend Costeen, she's helped open his eyes again. There was a lot of chaos in Nick's life before he met her," he said.

"On Sunday night, I believe the rest of the world will get Nick Kyrgios the Wimbledon champion. For us, we've already got our baby brother back. Mum and Dad have got their son back.

"He is already a champion in all our eyes. Seeing him mature and evolve back into the happy fulfilled version of himself is all that I could have asked for ... I just want to see him winning in all aspects of life."

Kyrgios is the first Australian since 2003 to reach the men's singles final at Wimbledon and he will take on Novak Djokovic for the title.