Nick Kyrgios has paid an emotional tribute to his hospitalised mother after sport’s enigma claimed his biggest scalp of the season, continuing his stunning form.

Australia’s Wimbledon runner-up defeated world no.1, Daniil Medvedev, in their second-round clash at the ATP Montreal Masters on Thursday, coming from a set down to win  6-7 (2-7) 6-4 6-2.

Kyrgios is in career-best form, winning 14 of his last 15 matches ahead of the US Open, as well as breaking his three-year singles title drought at the Washington Open last week.

He also claimed the doubles title at the Atlanta Open, alongside fellow Australian Thanasi Kokkinakis, earlier this month.

But while Kyrgios finds his stride on the court, the Australian tennis star has admitted to difficulty being away from home.

After the match, Kyrgios signed the television camera “Be Strong Ma” in a message who his mother Norlaila, who is in hospital.

“It’s hard because even travelling now, my mum is in hospital at the moment, my dad hasn’t been very well, my brother just had a baby and I don’t get to be there with my family when normal people would like to be with them,” Kyrgios said in his post-match press conference.

“It’s hard being from Australia because we can’t travel back and forth. There’s a lot of things people don’t see.

“They only see me winning, losing, throwing a racquet, doing those things. They don’t really understand the challenges that I face or what people on tour face, what’s going on in their personal lives.”

Kyrgios, who faces Australian No.1 Alex de Minaur next for a quarter-final spot, isn’t getting carried away despite firming as one of the US Open favourites following his rousing victory over last year’s Flushing Meadows champion.

His only defeat in his past 15 matches was to Novak Djokovic at Wimbledon. His victory over Medvedev is also his third from four meetings with the world’s No.1.

“Look, a grand slam is much, much different to any other tournament,” he said.

“If I was in this position of a grand slam, you’ve still got to win another set and that’s not easy at all. He’s a machine.

“He’s the best player in the world for a reason and at a grand slam he’s a totally different beast.”

Nevertheless, Kyrgios continues to make a mockery of the rankings. The 27-year-old’s latest triumph has all but secured the Canberran an all-important seeding for the New York major starting on August 29.

“I feel confident in my body and my mentality going into the US Open but at the same time there’s so much time between then and now,” Kyrgios said.

“I’ve got to focus on this event and then Cincinnati. There’s so many things I’ve got to look forward to. I’m not even going to think about the US Open right now.

“I need to take care of my body.”

De Minaur set up a first-time meeting with Kyrgios with a 7-6 (7-4) 7-5 second-round win over Bulgarian Grigor Dimitrov, the 15th seed.

– with AAP