Results from the fourth day of the ATP Finals at London's O2 Arena on Wednesday (x denotes seeding): Singles Group Tokyo 1970 Alexander Zverev (GER x5) bt Diego Schwartzman (ARG x8) 6-3, 4-6, 6-3 Playing later Novak Djokovic (SRB x1) v Daniil Medvedev (RUS x4) Doubles Group Bob Bryan Marcel Granollers/Horacio Zeballos (ESP/ARG x4) bt Mate Pavic/Bruno Soares (CRO/BRA x1) 7-6 (7/4), 6-7 (4/7), 10-8 Playing later John Peers/Michael Venus (AUS/NZL x6) v Jurgen Melzer/Edouard Roger-Vasselin (AUT/FRA x7) afp