Dominic Thiem of Austria serves to Daniil Medvedev of Russia during their singles final tennis match at the ATP World Finals tennis tournament at the O2 arena in London.
AP Photo/Frank Augstein
Dominic Thiem of Austria celebrates winning a point against Daniil Medvedev of Russia during their singles final tennis match at the ATP World Finals tennis tournament at the O2 ar...
AP Photo/Frank Augstein
Daniil Medvedev of Russia plays a return to Dominic Thiem of Austria during their singles final tennis match at the ATP World Finals tennis tournament at the O2 arena in London.
AP Photo/Frank Augstein
Dominic Thiem of Austria reacts as he wins the first set against Daniil Medvedev of Russia during their singles final tennis match at the ATP World Finals tennis tournament at the ...
AP Photo/Frank Augstein
Daniil Medvedev of Russia plays a return to Dominic Thiem of Austria during their singles final tennis match at the ATP World Finals tennis tournament at the O2 arena in London.
AP Photo/Frank Augstein
Daniil Medvedev of Russia holds up the winners trophy after defeating Dominic Thiem of Austria in the final of the ATP World Finals tennis match at the ATP World Finals tennis tour...
AP Photo/Frank Augstein
Daniil Medvedev of Russia, right, holds up the winners trophy after defeating Dominic Thiem of Austria, left, in the final of the ATP World Finals tennis match at the ATP World Fin...
AP Photo/Frank Augstein
Daniil Medvedev of Russia holds up the winners trophy as confetti falls after defeating Dominic Thiem of Austria in the final of the ATP World Finals tennis match at the ATP World ...
Photo by AP/PTI
Wesley Koolhof of the Netherlands, left, and Nikola Mektic of Croatia, right, hold up the trophy after winning against Jurgen Melzer of Austria and Edouard Roger-Vasselin of France...
Photo by AP/PTI
Wesley Koolhof of the Netherlands, left, and Nikola Mektic of Croatia, right, celebrate as they win match point against Jurgen Melzer of Austria and Edouard Roger-Vasselin of Franc...
Photo by AP/PTI
Novak Djokovic of Serbia serves the ball during the semifinal match against Dominic Thiem of Austria at the ATP World Finals tennis tournament at the O2 arena in London.
AP Photo/Frank Augstein
Dominic Thiem of Austria serves the ball during the semifinal match against Novak Djokovic of Serbia at the ATP World Finals tennis tournament at the O2 arena in London.
AP Photo/Frank Augstein
Novak Djokovic of Serbia returns the ball to Dominic Thiem of Austria during their semifinal match at the ATP World Finals tennis tournament at the O2 arena in London.
AP Photo/Frank Augstein
Dominic Thiem of Austria reacts during the semifinal match against Novak Djokovic of Serbia at the ATP World Finals tennis tournament at the O2 arena in London.
AP Photo/Frank Augstein
Novak Djokovic of Serbia juggles with his racket during the semifinal match against Dominic Thiem of Austria at the ATP World Finals tennis tournament at the O2 arena in London.
AP Photo/Frank Augstein
Dominic Thiem of Austria celebrates after winning his semifinal match against Novak Djokovic of Serbia at the ATP World Finals tennis tournament at the O2 arena in London. Thiem be...
AP Photo/Frank Augstein
Novak Djokovic of Serbia leaves after losing his semifinal match against Dominic Thiem of Austria at the ATP World Finals tennis tournament at the O2 arena in London.
AP Photo/Frank Augstein
Novak Djokovic of Serbia, left, shakes hands with Dominic Thiem of Austria at the end of their semifinal match ATP World Finals tennis tournament at the O2 arena in London. Thiem b...
AP Photo/Frank Augstein
Rafael Nadal of Spain celebrates after winning a point during the semifinal match against Daniil Medvedev of Russia at the ATP World Finals tennis tournament at the O2 arena in Lon...
Photo by AP/PTI
Wesley Koolhof of the Netherlands, left, celebrates with Nikola Mektic of Croatia as they play against Marcel Granollers of Spain and Horacio Zeballos of Argentina in the double se...
Rafael Nadal is relishing his first last-four chance at the ATP Finals since 2015, though his only regret is fans cannot be in attendance at the O2 Arena.