Novak Djokovic sweeps past Marin Cilic at World Tour Finals Novak Djokovic swept past US Open champion Marin Cilic on a day of one-sided matches at the ATP World Tour Finals on Monday. The world number one began his campaign for a third straight title at the O2 Arena with a 6-1 6-1 win in 56 minutes. Djokovic joins Stan Wawrinka at the top of Group A after the Swiss earlier thrashed Tomas Berdych by the same score. The two singles matches required a combined one hour and 54 minutes. That Djokovic won the second match of the day was hardly a surprise, such is his dominance at the venue and over the opponent. He is unbeaten at the O2 since 2011, has won his last 27 matches indoors and went into Monday's encounter with a 10-0 record against Cilic. The Croat had taken sets off Djokovic three times in 2014 and must have felt optimistic after the seven-time Grand Slam champion edged through a nervy first service game. A little over half an hour later, Djokovic had reeled off seven straight games with his familiar combination of brilliant athleticism and precision hitting. Two running forehand passes helped the Serb break for 4-1, a third break gave him the set, and Cilic looked an understandably dispirited figure when he netted a forehand to go 2-0 down in the second. The following game provided a reminder of the Cilic who won the US Open, as he crushed two forehands to break for love, but the comeback was quickly snuffed out. Djokovic ratcheted up the pressure once again, peppering the baseline with his returns, and a desperate Cilic could not win another game. More follows.