Novak Djokovic won his fourth China Open title in five years , prevailing 6-3, 6-4 in the final against Rafael Nadal in Beijing today. Nadal will replace him as the men's new world number one tomorrow.The 26-year-old Djokovic stamped his authority on the title match early, racing to a 3-0 lead in the first set. He broke Nadal in the first game of the second set and clearly looked the better player, hitting winners almost at will.