World No. 2 Novak Djokovic thrashed Italy's Matteo Berrettini 6-2, 6-1 in their opening match at the ATP World Tour Finals. In the year-ending tournament, the five-time champion on Sunday gave the Berrettini little chance on court, grabbing the victory in just 64 minutes. Federer and Djokovic will meet later in the week in a repeat of this year's Wimbledon final.