World number two tennis star Novak Djokovic has admitted that he and his fiancee Jelena Ristic are yet to decide on a wedding date.

The couple announced their engagement in September following an eight-year romance.

When asked at the Australian Open whether a wedding was close, Djokovic said on court: "We do not have a date yet, but we're looking forward to it. We're keeping it our little secret."

Djokovic was speaking after he secured a straight-sets win over Lukas Lacko in the first round of the competition in Melbourne.