MADRID, SPAIN - NOVEMBER 22: Novak Djokovic of Serbia in action during his quarter final singles match against Karen Khachanov of Russia on Day Five of the 2019 Davis Cup at La Caja Magica on November 22, 2019 in Madrid, Spain. ( Burak Akbulut - Anadolu Agency )
MADRID, SPAIN - NOVEMBER 22: Karen Khachanov of Russia in action during his quarter final singles match against Novak Djokovic of Serbia on Day Five of the 2019 Davis Cup at La Caja Magica on November 22, 2019 in Madrid, Spain. ( Burak Akbulut - Anadolu Agency )
MADRID, SPAIN - NOVEMBER 22: Novak Djokovic (R) of Serbia greets Karen Khachanov of Russia after the quarter final singles match on Day Five of the 2019 Davis Cup at La Caja Magica on November 22, 2019 in Madrid, Spain. ( Burak Akbulut - Anadolu Agency )
MADRID, SPAIN - NOVEMBER 22: Novak Djokovic of Serbia in action during his quarter final singles match against Karen Khachanov of Russia on Day Five of the 2019 Davis Cup at La Caja Magica on November 22, 2019 in Madrid, Spain. ( Burak Akbulut - Anadolu Agency )
MADRID, SPAIN - NOVEMBER 22: Novak Djokovic of Serbia in action during his quarter final singles match against Karen Khachanov of Russia on Day Five of the 2019 Davis Cup at La Caja Magica on November 22, 2019 in Madrid, Spain. ( Burak Akbulut - Anadolu Agency )
MADRID, SPAIN - NOVEMBER 22: Novak Djokovic of Serbia in action during his quarter final singles match against Karen Khachanov of Russia on Day Five of the 2019 Davis Cup at La Caja Magica on November 22, 2019 in Madrid, Spain. ( Burak Akbulut - Anadolu Agency )
MADRID, SPAIN - NOVEMBER 22: Novak Djokovic of Serbia in action during his quarter final singles match against Karen Khachanov of Russia on Day Five of the 2019 Davis Cup at La Caja Magica on November 22, 2019 in Madrid, Spain. ( Burak Akbulut - Anadolu Agency )
MADRID, SPAIN - NOVEMBER 22: Novak Djokovic of Serbia in action during his quarter final singles match against Karen Khachanov of Russia on Day Five of the 2019 Davis Cup at La Caja Magica on November 22, 2019 in Madrid, Spain. ( Burak Akbulut - Anadolu Agency )
MADRID, SPAIN - NOVEMBER 22: Novak Djokovic of Serbia in action during his quarter final singles match against Karen Khachanov of Russia on Day Five of the 2019 Davis Cup at La Caja Magica on November 22, 2019 in Madrid, Spain. ( Burak Akbulut - Anadolu Agency )