In Tennis, world number one Andy Murray has begun his ATP World Tour Finals campaign with a convincing win in London. Murray, who had replaced Novak Djokovic at the top of the rankings last week, won his opening group game of the season finale 6-3, 6-2 against Croatia's Marin Cilic yesterday to register his 20th victory in a row.Both, Murray and Djokovic are vying for the year-end number one spot.Djokovic had won his opener against Dominic Thiem on Sunday.In yesterday's other group match, Kei Nishikori stunned Stanislas Wawrinka 6-2, 6-3.Today, Djokovic will take on Milos Raonic, while Thiem will meet Gael Monfils in their second group games.