Who is playing in the ATP Cup?
Serbia: Novak Djokovic, Dusan Lajovic, Filip Krajinovic, Nikola Cacic
Spain: Rafael Nadal, Roberto Bautista Agut, Marcel Granollers, Pablo Carreno Busta
Austria: Dominic Thiem, Dennis Novak, Philipp Oswald, Tristan-Samuel Weissborn
Russia: Daniil Medvedev, Andrey Rublev, Aslan Karatsev, Evgeny Donskoy
Greece: Stefanos Tsitsipas, Michail Pervolarakis, Markos Kalovelonis, Petros Tsitsipas
Germany: Alexander Zverev, Jan-Lennard Struff, Kevin Krawietz, Andreas Mies
