Stefanos Tsitsipas (6), Greece, def. Daniil Medvedev (4), Russia, 7-6 (5), 6-4.
Alexander Zverev (7), Germany, def. Rafael Nadal (1), Spain, 6-2, 6-4.
Kevin Krawietz and Andreas Mies (3), Germany, def. Horia Tecau, Romania, and Jean-Julien Rojer (6), Netherlands, 7-6 (3), 4-6, 10-6.
Nicolas Mahut and Pierre-Hugues Herbert (7), France, def. Robert Farah and Juan Sebastian Cabal (1), Colombia, 6-3, 7-5.Monday
At The O2 Arena
Surface: Hardcourt indoor
LONDON (AP) _ Results Monday from World Tour Finals Singles at The O2 Arena (seedings in parentheses):
Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.