Last year, Novak Djokovic was not beaten until June, but he's already lost in Melbourne -- to a little girl. The child challenged the World No 1 after watching him practise this week.

Novak Djokovic Pic/ AFP

"Her mum said, 'Novak, I think my daughter can beat you. So I said, 'OK, give it a shot'. So we played and she won, three points to two," recalled the Serb. "That was the first loss of the season."