PARIS, Dec. 18 (Xinhua) -- Novak Djokovic and Serena Williams were titled the men's and women's World Champions for 2014 by the International Tennis Federation (ITF) Thursday.

In 2014, the 27-year-old Djokovic has won Wimbledon, the ATP World Tour finals and finished the year ranked number one in the world by the ATP.

The 33-year-old Williams, the oldest player ever to be named an ITF Singles World Champion, won the US Open, the 18th Grand Slam title of her career, the ATP Tour Championship and was also ranked number one by the WTA.

Americans Bob and Mike Bryan were named men's doubles World Champions for the 11th time in 12 years, while Sara Errani and Roberta Vinci of Italy became women's doubles World Champions for the third successive year.