Nadal, Murray through to Miami 4th round

Second-seeded Rafael Nadal and No. 4 Andy Murray each advanced Sunday with third-round victories in the Sony Ericsson Open. Nadal, seeking his first Miami title, had little trouble in his 6-2, 6-2 victory over the 25th-seeded Radek Stepanek, remaining perfect at 6-0 in his career against the Czech veteran. The Spanish star, who was bested by Novak Djokovic in last year\'s final, now goes on to face 16th-seeded Kei Nishikori of Japan, who moved on with a 6-4, 6-2 verdict over unseeded Czech Lukas Rosol. Murray, meanwhile, advanced to the fourth round after Canadian opponent Milos Raonic withdrew with an ankle sprain. The 2009 Miami champ will take on No. 13 seed Gilles Simon following the Frenchman\'s 7-6 (7-5), 6-4 win over 22nd-seeded Jurgen Melzer of the Czech Republic. Sixth-seeded Jo-Wilfried Tsonga of France also moved on with a 6-4, 7-6 (7-2) win over 32nd-seeded German Phillipp Kohlschreiber. Next up for him is 19th-seeded Florian Mayer of Germany, who got past No. 10 seed John Isner of the United States 6-4, 6-2. In another upset, seventh-seeded Czech Tomas Berdych fell 6-3, 2-6, 6-4 to Belgian Grigor Dimitrov.