( CNN ) -- World No . 2 Rafael Nadal is still on course for his first Miami Masters title after beating the Czech Republic 's Radek Stepanek 6-2 6-2 in the third round of the U.S. hard-court tournament . Spain 's 10-time grand slam winner has been runner-up at the event on three occasions , including last year when he lost to Novak Djokovic , who went on to dethrone him at the top of the rankings . Nadal took just 87 minutes to record a sixth consecutive win over 25th seed Stepanek on Sunday , setting up a clash with No . 16 Kei Nishikori -- who also beat Czech opposition in the shape of Lukas Rosol . `` He 's a fantastic player and it will be a very difficult match for me , '' Nadal said of Japan 's 22-year-old rising star . `` He has a big talent to hit the ball very early , to play very aggressive . So he will be a really tough opponent . '' World No . 4 Andy Murray reached the last 16 without hitting a ball , after his in-form third-round opponent Milos Raonic was forced to pull out due to an ankle injury in Key Biscayne . `` The doctor does n't think it 's anything big . It probably just needs a couple days of rest and , with treatment , it should be OK in a week , '' said the Canadian , who has already won titles in Chennai and San Jose this year . Murray will now face Gilles Simon for a place in the quarterfinals after the French 13th seed won 7-6 6-4 against Austrian 22nd seed Jurgen Melzer . In other third-round matches , seventh-seeded Czech Tomas Berdych slumped to a shock 6-3 2-6 6-4 defeat by Grigor Dimitrov , who beat a top-10 player for the first time in his career . The Bulgarian next faces Serbian ninth seed Janko Tipsarevic , who saw off Ukrainian No . 18 Alexandr Dolgopolov 6-4 5-7 6-2 . French sixth seed Jo-Wilfried Tsonga defeated No . 32 Philipp Kohlschreiber 6-4 7-6 , and will next face another German -- No . 19 Florian Mayer . The winner of that match will face Nadal or Nishikori . In the women 's section , the unseeded Venus Williams , who was handed a wildcard to compete in Florida , is also through to the last 16 . The American , who was diagnosed with the incurable Sjogren 's syndrome before the 2011 U.S. Open , was made to battle hard before defeating Canadian Aleksandra Wozniak 4-6 6-4 7-6 . She next faces fellow former world No . 1 Ana Ivanovic . The Serbian 15th seed overcame Slovakia 's No . 20 Daniela Hantuchova 6-2 7-6 ( 7-2 ) . World No . 1 Victoria Azarenka , the defending champion , thrashed British wildcard Heather Watson 6-0 6-2 . The Australian Open champion will play No.16 Dominika Cibulkova after the Slovakian beat China 's Zheng Jie . Polish fifth seed Agnieszka Radwanska set up a clash with Spanish wildcard Garbine Muguruza Blanc , who shocked Italy 's No . 24 Flavia Pennetta 6-2 1-6 7-6 . French seventh seed Marion Bartoli will face Russia 's No . 22 Maria Kirilenko in the last 16 after both won comfortably .
fourth seed Andy Murray through to the fourth round of Miami Masters . The 6 -time runner-up at the U.S. hard-court event beat Czech Andy Murray . No . 4 Milos Raonic handed a walkover after opponent Milos Raonic had to withdraw . Murray handed a walkover after opponent Milos Raonic had to withdraw through injury .