Djokovic wins ATP World Tour title
Novak Djokovic capped a remarkable season beating Roger Federer to claim a record fourth straight ATP World Tour Finals title.
The world no.1 beat his long-time rival 6-3 6-4 in a one-sided title match at the O2 Arena which lasted just 81 minutes.
With this, Djokovic has drawn level with Federer in their head to head at 22 wins each
The Tour: World tour finals
The ATP World Tour Finals is the season-ending championship of professional men's tennis played on indoor hard court.
It is held annually in November at the O2 Arena in London, United Kingdom.
First held in 1970, the tour features top eight singles players and doubles teams of the ATP rankings.
The current champions (2014) are Novak Djokovic in singles and Bryan brothers in doubles.
Format : What is the tour's format?
Unlike all other singles men's tennis events, the ATP World Tour Finals is not a straightforward knock-out tournament.
Eight players are divided into two groups of four and play three round-robin matches each against other players in their group.
The two players with best records in each group progress to the semifinals, whose winners meet in the final to play for the title.
Fact: The 2015 top 8
The top 8 players who qualified to play the year-end world tour finals in singles for the year 2015 in order of their ranking were - Novak Djokovic, Andy Murrray, Roger Federer, Stan Wawrinka, Rafael Nadal, Tomas Berdych, David Ferrer and kei Nishikori.
15-20 Nov 2015: Group Matches
Djokovic, Federer, Berdych and Nishikori were put together under Group A-Stan Smith Group.
Murray, Wawrinka, Nadal and Ferrer played each other in Group B-llie Nastase group.
Federer emerged on top Group A unbeaten with Djokovic coming second having lost only one match, to Federer.
Nadal came top of the Group B unbeaten while Wawrinka won a tight contest beating Murray to finish second.
21 Nov 2015: About the semi-final matches
The semi final matches had Roger Federer facing his fellow compatriot Stan Wawrinka and Nadal against Djokovic.
Djokovic beat Nadal in straight sets 6-3, 6-3 to reach the tournament final.
Federer also overcame Wawarinka easily in two sets 7-5, 6-3 to enter the final round.
This would be the 10th year-end championship final for Federer, who had previously won 6 of them.
Fact: ATP Tour Doubles winners
The 2015 ATP World Tour Finals Doubles championship was won by the pair Jean-Julien Rojer of Netherlands and Horia Tecau of Romania beating Rohan Bopanna of India and Florin Mergea of Romania in straight sets 6-4, 6-3.
23 Nov 2015: Djokovic wins ATP World Tour title
Fact: 2015 stats for Djokovic
In 2015 Novak Djokovic reached 15 finals, won 11 titles which includes 3 Grand Slams, 6 ATP 1000 Masters and the year-end ATP world tour finals. He achieved a win-loss record of 82-6.