Top seed Novak Djokovic of Serbia and No. 5 seed Andrey Rublev of Russia were winners Monday as group action continued at the Nitto ATP Finals in Turin, Italy. Djokovic won a first-set tiebreak en route to a 7-6 (4), 6-2 victory over No. 8 Casper Ruud of Norway. Rublev upset No. 4 seed Stefanos Tsitsipas of Greece 6-4, 6-4. Djokovic won 35 of 39 first-service points (89.7 precent) and recorded 10 aces in his first match