Novak Djokovic reveals the secret to his slides - skiiing

World number one Novak Djokovic on Friday revealed the secret to his uncanny ability to slide across hard courts -- an upbringing steeped in skiing.

The defending Australian Open champion reached the fourth round 6-4, 6-3, 7-5 against Czech veteran Radek Stepanek, and was then asked how he could execute his trademark sideways skids without getting injured.

"I believe that it comes from my skiing," Djokovic said. "My father used to be a professional skiier and so were a lot of members of my family. I guess I developed it then on the snow and it's quite natural for me now."

Djokovic was raised at Mount Kopaonic in Serbia where his father and mother, Srdjan and Dijana, operated a restaurant and conducted ski lessons.

It was at Mount Kopaonic that a six-year-old Djokovic had his first tennis lesson with his childhood coach, Jelena Gencic.