SERBIA’s Novak Djokovic has beaten Andy Murray to the International Tennis Federation’s annual men’s world champion award with American Serena Williams taking the women’s prize for a third time.Djokovic, who ended a second successive year on top of the ATP rankings, successfully defended his Australian Open title, reached the final at the French Open and US Open and claimed five other titles including the season-ending Tour Finals.Britain’s Murray was a strong contender for the honour after beating Djokovic at the US Open to win his first major title after four losses in finals and claiming Olympic gold at Wimbledon, just weeks after reaching the Grand Slam final there in which he lost to an inspired Roger Federer.“I am proud to have been named ITF world champion for the second successive year,” Djokovic, who dominated 2011 with three of the four Slam titles, said.“It was very difficult to follow up such a successful season in 2011, but it was extremely satisfying to win another Grand Slam title, reach two other major finals and finish the year at number one.”The 31-year-old Williams was unstoppable in the second half of 2012, winning Wimbledon, singles and doubles gold at the Olympics and the US Open.