Novak Djokovic reclaimed the world No.1 ranking on Monday after a two-year absence and is assured of finishing the year there.
Rafael Nadal on Monday confirmed that he will miss the ATP Finals in London and announced the "end of the season" because of injury.
He hasn't competed since he retired from his U.S. Open semifinal against Juan Martin del Potro because of a painful right knee.
"We had detected it for some time and it occasionally bothered me". The Serbian will now become the first player since ATP rankings were introduced in 1973 to end the year at number one having started it outside the top 20.
The 32-year-old won a record-extending 11th French Open title in June and reached the semi-finals both at Wimbledon and the US Open.
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We're seeing them create very little but be efficient with the chances the do have". Barca have done well without Messi.
Djokovic's dominant run ended on Sunday when he was beaten 7-5, 6-4 by Russian Kharen Khachanov in the Paris Masters final.
Rafael Nadal of Spain hits to Dominic Thiem of Austria in a quarter-final match on day nine of the 2018 US Open tennis tournament at USTA Billie Jean King National Tennis Center in NY, on Sept 4, 2018.
Top seed Djokovic returned to the top of the world rankings following Rafael Nadal's withdrawal from last week's Paris Masters due to injury.
Rafa Nadal will not take part in the ATP Finals and waves goodbye to the rest of the season.
"Since the problem in my abdominal muscle also prevents me from playing in London, we have made a decision to take advantage of the moment. and avoid future problems".
Novak Djokovic of Serbia returns the ball to Karen Khachanov of Russian Federation during their final match of the Paris Masters tennis tournament at the Bercy Arena in Paris, France, Sunday, Nov. 4, 2018.