London, England (SportsNetwork.com) - Former top-ranked star Novak Djokovic and current women's world No. 1 Serena Williams have been selected as the International Tennis Federation's world champions for 2013.
Djokovic won for a third straight year, while Williams was honored for the fourth time in her brilliant career.
The Serbian stalwart Djokovic started his '13 season by capturing a third straight and fourth overall Australian Open title and was the runner-up at Wimbledon and the U.S. Open. The 26-year-old finished the year ranked second in the world after corralling seven titles.
The 32-year-old Williams was the French and U.S. Open champion on her way to her first year-end No. 1 finish in four years.
Both Djokovic and Williams also captured the lucrative season-ending events on the ATP and WTA tours, the ATP World Tour Finals and WTA Championships, respectively.
American twin brothers Bob Bryan and Mike Bryan were named men's doubles world champs for the 10th time in 11 years, while Italy's Sara Errani and Roberta Vinci claimed the women's doubles award.