Heartache inspires Kyrgios

Tennis golden boy Nick Kyrgios has opened up about the heartache that's driving him to succeed and carry the mantle of Australia's brightest grand slam hope.

The world No.53 left fans scratching their heads when he dropped to his knee and gestured to the heavens after his first round victory over Frederico Debonis before signing the number 74 on a camera lens.

But Kyrgios has revealed the motivation behind his actions – honouring his late grandmother, Julianah Foster.

Mrs Foster died in a West Albury nursing home, in NSW, on July 13 last year aged 74 and her passing remains a motivating factor every time the teenager hits the court.

"My grandma passed away last year, that is something I still think about every day, and that’s probably made me a little bit more mature," Kyrgios said.

"She was practically my mum when I was a kid. My mum was always working so she was taking me to tennis training every day, taking me school, picking me up from school.

"She was also living at our house so she was a massive influence."

Recovering from a back injury and playing only his second match of the year, Kyrgios was forced to dig deep in his five set victory over Debonis, which finished after midnight on Monday night.

But speaking after the match, the 19-year-old said as always his grandmother was on his mind.

You may be gone, but I know you are watching. #74 #motivation pic.twitter.com/uVjrcbwxHV

— Nicholas Kyrgios (@NickKyrgios) January 19, 2015

Kyrgios came of age at Wimbledon last year with his stunning victory over Rafael Nadal en route to a quarter final appearance, which he says gave him pride his grandmother was around to savour.

"She passed just after Wimbledon, I was just glad she saw me playing, and that she finally saw me on that stage," he said.

"You walk into her room in Albury, she has posters and pictures of me. It was great she finally saw me on the top stage."

He said every performance was now in memory of the motherly figure.

"I am playing for her a little bit now," he said ahead of his second round showdown with big serving Croatian Ivo Karlovic on Wednesday.

"Every time I am out on the court, I’m always thinking about something that is going to motivate me, and that’s probably the reason I’m starting to train harder and knuckle down a bit more now."