World number one Novak Djokovic has opened up about the economic problems that threatened to block his dreams of becoming a tennis professional.

The Belgrade-born 25-year-old, who has five Grand Slam titles to his name, says that he owes his success to the sacrifices made by his family during his childhood.

He told CNN: "I remember as a kid improvising and making little trophies out of different materials and going in front of the mirror lifting the trophies and saying I was a champion.

"At that time in Serbia our tennis was nowhere. We grew up during the war and then there was a lot of financially struggles and it was difficult to travel to the tournaments, so we played many of the local national tournaments.

"I had to try really hard to succeed and I had to thank God for the support from my family - they believed in me and they gave me hope that I can really actually succeed."

Djokovic has already earned over £28m in competition prize money during his career.