World number one Novak Djokovic cruised into the semi-finals of the ATP and WTA Western & Southern Open on Wednesday while Japan's Naomi Osaka withdrew to protest the shooting of a black man by police in Wisconsin. Djokovic, who launches his bid for a fourth US Open title and 18th Grand Slam crown on Monday, needed only 62 minutes to rout Germany's Jan-Lennard Struff 6-3, 6-1. The 33-year-old Serbian, who seeks a fourth US Open title and 18th Grand Slam crown, advanced to a Thursday semi-final against Spain's Roberto