novak djokovic defeated david ferrer 7-5 , 7-5 to reach miami open semis .
briton andy murray to meet tomas berdych in other semi-final match .
djokovic has beaten murray in australian open final and at indian wells .
world no 1 now faces john isner , who beat kei nishikori 6-4 , 6-3 .
serena williams and carla suarez navarro will contest women 's final .
world no 1 williams beat simona halep to 6-2 , 4-6 , 7-5 .
navarro comfortably defeated andrea petkovic 6-3 , 6-3 .