The 2015 ATP World Tour Finals (also known as the 2015 Barclays ATP World Tour Finals for sponsorship reasons) was a men's tennis year-end tournament that was played at the O2 Arena in London, United Kingdom, between 15 and 22 November 2015. It was the season-ending event for the best singles players and doubles teams on the 2015 ATP World Tour.

Finals

Singles

Novak Djokovic defeated Roger Federer 6–3, 6–4 It was Djokovic's 11th title of the year and 59th of his career. It was his 5th win at the event, winning in 2008, 2012, 2013, and 2014.

Doubles

Jean-Julien Rojer / Horia Tecău defeated Rohan Bopanna / Florin Mergea 6–4, 6–3

Tournament

The 2015 ATP World Tour Finals took place from 15 to 22 November at the O2 Arena in London, United Kingdom. It is the 46th edition of the tournament (41st in doubles). The tournament is run by the Association of Tennis Professionals (ATP) and is part of the 2015 ATP World Tour. The event takes place on indoor hard courts. It serves as the season-ending championships for players on the ATP Tour. The eight players who qualify for the event are split into two groups of four. During this stage, players compete in a round-robin format (meaning players play against all the other players in their group). The two players with the best results in each group progress to the semi-finals, where the winners of a group face the runners-up of the other group. This stage, however, is a knock-out stage. The doubles competition uses the same format.

Format

The ATP World Tour Finals has a round-robin format, with eight players/teams divided into two groups of four. The eight seeds are determined by the ATP rankings and ATP Doubles Team Rankings on the Monday after the last ATP World Tour tournament of the calendar year. All singles matches are the best of three tie-break sets, including the final. All doubles matches are two sets (no ad) and a Match Tie-break.

Group name changes The ATP has announced that the group names will be changed from A and B to that of former champions of the event. In 2015 the groups will be renamed after the first two champions Stan Smith (1970) and Ilie Năstase (1971–73, 75).

Points and prize money StageSinglesDoubles1PointsChampionRR + $1,560,000RR + $245,000RR + 900Runner-upRR + $510,000RR + $83,000RR + 400$167,000$32,000200Participation fee RR1$100,000$82,000Participation fee RR2$25,000Participation fee RR3$42,000Alternates$95,000$32,000 RR is points or prize money won in the round robin stage. 1 Prize money for doubles is per team. An undefeated champion would earn the maximum 1,500 points and $2,228,000 in singles

Qualification

Singles Eight players compete at the tournament, with two named alternates. Players receive places in the following order of precedence: First, the top 7 players in the ATP rankings on the Monday after the final tournament of the ATP World Tour, that is, after the 2015 Paris Masters. Second, up to two 2015 Grand Slam tournament winners ranked anywhere 8th–20th, in ranking order Third, the eighth ranked player in the ATP rankings In the event of this totaling more than 8 players, those lower down in the selection order become the alternates. If further alternates are needed, these players are selected by the ATP.

Provisional rankings are published weekly as the ATP Race to the World Tour Finals, coinciding with the 52-week rolling ATP rankings on the date of selection. Points are accumulated in Grand Slam, ATP World Tour, Davis Cup, ATP Challenger Tour and ITF Futures tournaments from the 52 weeks prior to the selection date, with points from the previous years Tour Finals excluded. Players accrue points across 18 tournaments, usually made up of:

The 4 Grand Slam tournaments The 8 mandatory ATP Masters tournaments The best results from any 6 other tournaments that carry ranking points

All players must include the ranking points for mandatory Masters tournaments for which they are on the original acceptance list and for all Grand Slams for which they would be eligible, even if they do not compete (in which case they receive zero points). Furthermore, players who finished 2014 in the world's top 30 are commitment players who must (if not injured) include points for the 8 mandatory Masters tournament regardless of whether they enter, and who must compete in at least 4 ATP 500 tournaments (though the Monte Carlo Masters may count to this total), of which one must take place after the US Open. Zero point scores may also be taken from withdrawals by non-injured players from ATP 500 tournaments according to certain other conditions outlined by the ATP. Beyond these rules, however, a player may substitute his next best tournament result for missed Masters and Grand Slam tournaments.

Players may have their ATP World Tour Masters 1000 commitment be reduced by one tournament, by reaching each of the following milestones: 600 tour level matches (as of 1 January 2015), including matches from Challengers and Futures played before year 2010; 12 years of service; 31 years of age (as of 1 January 2015). Players must be defined by the ATP as in good standing to avail of the reduced commitment.

Doubles Eight teams compete at the tournament, with one named alternates. The eight competing teams receive places according to the same order of precedence as in Singles. The named alternate will be offered first to any unaccepted teams in the selection order, then to the highest ranked unaccepted team, and then to a team selected by the ATP. Points are accumulated in the same competitions as for the Singles tournament. However, for Doubles teams there are no commitment tournaments, so teams are ranked according to their 18 highest points scoring results from any tournaments.

Qualified players

Singles #PlayersPointsToursDate qualified115,285154 June28,4701915 August37,340178 September46,500229 September54,6302218 October64,6202118 October74,3051931 October 84,0352031 October

On 4 June 2015, Novak Djokovic was announced as the tournament's first qualifier upon reaching the semi-finals of the 2015 French Open.

Novak Djokovic began his season in Qatar ExxonMobil Open, where he reached the quarterfinals before losing to Ivo Karlović in a tight three set match. He then went on to reach the final of every subsequent tournament he played, beginning with reclaiming the Australian Open title, defeating Andy Murray in four sets to become the first man in the Open Era to win five titles in Melbourne. After losing the final in Dubai Tennis Championships to Roger Federer, Djokovic went on a 28-match winning streak, first leading Serbia to the quarterfinals of the Davis Cup before winning the first three Masters 1000 titles of the year at the BNP Paribas Open, Miami Open and Monte-Carlo Rolex Masters, beating Federer, Murray and Tomáš Berdych respectively in the finals.

After skipping Madrid, he successfully defended his title at the Rome Masters, defeating Federer in the final once again. At the French Open, Djokovic once again made it to the final, defeating Murray en route in a gruelling 5-set thriller in the semi-finals. Ultimately he lost the final to Stan Wawrinka, denying the Serb a first title in Paris and a Career Grand Slam. He quickly rebounded to win his third Wimbledon title, defeating Federer in the final for the second year in a row to successfully defend his title. In the first tournament of the US Open Series, Djokovic made it to the final of the Canada Masters for only the fourth time, making it to the final before losing to Murray in what was his first loss in nine encounters with the Scot. The next week, at the Western & Southern Open, Djokovic made it to the finals for the fifth time, but was once again defeated, this time by Roger Federer. This was the fifth time that Djokovic had been defeated in the finals of Cincinnati, the only ATP World Tour Masters 1000 title he has never won.

At the final slam of the year, the US Open, Djokovic was victorious, defeating Roger Federer in the finals. This victory meant Djokovic won 3 of the 4 Grand Slams in 2015; this is the second time he achieved this feat in his career, the other year being 2011 Novak Djokovic Tennis Season. In making it to the final, Djokovic reached the final of all 4 Grand Slams this year, achieving this feat for the first time in his career. After his US Open victory, Djokovic continued his triumph by winning the China Open defeating Rafael Nadal in the finals, thus extending his winning streak to 12 and extended his winning streak to 30 matches won in a row in Beijing, where he has never lost in his six appearances. Djokovic then ventured to the Shanghai Rolex Masters as a three-time champion he was once again victorious, defeating Jo Wilfried Tsonga in the final. This marked the fifth Masters 1000 title of the year for Djokovic, tying the record for most Masters 1000 titles won in a single season. In the next tournament, the Paris Masters, Djokovic made history by winning his sixth Masters in 2015, the most Masters anyone has won in a single season with his victory over Andy Murray. His Masters 1000 tally was increased to 26, putting him one shy of Rafael Nadal who holds the record with 27. Djokovic is set to make his ninth consecutive appearance at the season finale.

On 15 August, Andy Murray became the second player to qualify on 15 August, during his victorious campaign at the Rogers Cup.

Andy Murray opened his campaign at the Hopman Cup, where he was partnered by Heather Watson. The Brits finished their group second behind Poland, despite being level on ties and matches won, however Murray won each of his singles matches against Benoît Paire, Jerzy Janowicz and Marinko Matosevic respectively. Murray's first competitive tournament of the year was the Australian Open, where he made it to the final for the fourth time, however lost to Novak Djokovic, becoming the first man in the Open Era to lose four Australian Open finals. After quarterfinal losses in both ABN AMRO World Tennis Tournament and Dubai Tennis Championships to Gilles Simon and Borna Ćorić respectively, Murray made it to the semi-finals in BNP Paribas Open, and his fourth final in Miami Open, losing to Djokovic in both instances.

He then went on to have his most successful clay court season to date, reaching his first ever final on clay at the BMW Open in Munich. He defeated home favourite Philipp Kohlschreiber in the final to claim the first clay title of his career. This was followed up by reaching his first Masters 1000 final on clay, defeating three top 10 opponents in succession for the first time on clay, including a first clay court victory over Rafael Nadal, to win the title at the Madrid Open for the first time since 2008. Murray withdrew prior to his third round match against David Goffin in Rome Masters, citing fatigue, before reaching his third semi-final at the French Open, losing again to Djokovic in a thrilling five-set encounter. Murray began his grass court season by winning his fourth title at the Queen's Club, joining John McEnroe, Lleyton Hewitt and Andy Roddick for the most titles at the tournament in the Open Era. He made it to the semi-finals at Wimbledon, losing to Roger Federer in straight sets.