Britain's Andy Murray beat five-time champion Novak Djokovic to win his first ATP World Tour Finals title and end 2016 as the world number one.
With the year-end top ranking on the line, Murray won the much-anticipated final 6-3 6-4 at London's O2 Arena.
He said he was very happy to win and to be world number one is very special. He also added that it was very special playing against Novak Djokovic.
The victory also ends Djokovic's four-year run of success at the tournament and the Serb's bid to equal Roger Federer's record of six titles.