Top-ranked Novak Djokovic and Serena Williams have been named as the 2015 ITF World Champions to cap off a spectacular season, which saw them lift three Grand Slam titles this year.
Djokovic extended his Grand Slam tally to 11 titles after winning the Australian Open, Wimbledon and the US Open in 2015. The Serbian described the season as the best of his career, Sport24 reported.
Meanwhile, Williams claimed the Australian Open, the French Open and Wimbledon before failing to complete a calendar Grand Slam in the US Open. She produced an imperious form to end the season with a 53-3 win-loss record.