Tennis sensation Carlos Alcaraz did not have the best of starts to his ATP Finals journey, as the 20-year-old Spaniard lost to two-time champion Alexander Zverev 6-7 (3), 6-3, 6-4 on his debut in Turin on Monday. Zverev served 16 aces to Alcaraz's 11, saved five of six break points, and never really let Alcaraz feel in control. Alcaraz had missed the finals last year because of an abdominal injury. The Spaniard can still hope to advance from the round-robin, with the top two finishers in each four-man group reaching the semi-finals.