Novak Djokovic has split from coach Boris Becker after three years working together.
Djokovic hired the former world number one ahead of the 2014 season in what was widely seen as a surprising move, but critics were silenced as the Serbian won six grand slam titles and dominated the sport.
Announcing the news on his Facebook page, Djokovic said: "After three very successful years, Boris Becker and I have jointly decided to end our cooperation
"The goals we set when we started working together have been completely fulfilled, and I want to thank him for the cooperation, teamwork, dedication and commitment.
"On the other hand, my professional plans are now directed primarily to maintain a good level of play, and also to make a good schedule and new goals for the next season. In this regard I will make all future decisions."
Andy Murray beat Novak Djokovic in straight sets in the World Tour Final - sealing his position as world number one for the rest of 2016.
The Wimbledon champion, who shot to the top of the world rankings a fortnight ago, would have been knocked off his spot if Djokovic had won.
It is the fifth title in a row the Scotsman has won, bringing his winning run to 24 matches.
Speaking at the O2 Arena in London, Murray, 29, said: "Obviously it's a very special day.
"Playing against Novak in a match like this, we've played grand slam finals, Olympics - it's been a tough rivalry.
"I've lost many of them - I'm very happy I managed to win today.
"To finish the year number one is something I never expected."
Andy Murray is one win away from topping the men's tennis world rankings for the first time.
Novak Djokovic's defeat at the Paris Masters means the Serbian's two-year reign as the world number one could end if Murray claims victory in the event's semi-finals on Saturday.
Three-time grand slam winner Murray came through his quarter-final with Tomas Berdych 7-6 7-5 while 12-time slam winner Djokovic lost 6-4 7-6 to Marin Cilic.
"Maybe a little bit before the match there were a few more nerves but once I got out there I didn't let it affect me," the Scot said.
"My goal wasn't to get to number one this year, I was looking at the beginning of next year as the chance to do it. If it happens this week then great."
Murray will play Jo-Wilfried Tsonga or Milos Raonic in Saturday's semi-final, which begins at 3.30pm, where victory would give him enough ranking points to surpass Djokovic.
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Novak Djokovic has left the Rio 2016 court in tears after a surprise first round defeat to an opponent who got stuck in a lift on the morning of the match.
Former US Open champion Juan Martin Del Potro, who is now ranked 141st in the world after a series of injury problems, won 7-6 (7-4) 7-6 (7-2) to end the top men's seed's hopes of an Olympic tennis medal.
Del Potro had earlier been trapped in an Olympic Village lift for 40 minutes before being rescued by members of Argentina's handball team.
This is how Delpo started the day: trapped in an elevator at the Olympic village for 40 minutes. https://t.co/EFNmOKqIwE
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Thousands of tickets for Wimbledon's People's Sunday sold out in just 27 minutes.
For only the fourth time in its 139-year history there were be play on the middle Sunday of the tournament after rain disrupted the tennis championship's scheduling leaving a backlog of matches.
Tickets cost up to £70 and sold out with fans not knowing who they can expect to see play.
The 10,000 Centre Court tickets at the top price, 8,000 £40 tickets for Court One, and 4,000 ground passes at £20 went on sale at 3pm.
Many fans were left empty handed though, with 111,000 queuing for the 22,000 tickets which were sold at a rate of 815 per minute.
More upset than the empty-handed fans was defending champion Novak Djokovic, who was knocked out by American Sam Querrey.
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