Video Related To: Canada's Milos Raonic advances at Japan Open after opponent retires

The Spanish world number one was asked plenty of questions by his Czech opponent, but consistently had the answers as he broke twice in each set to win. Stepanek's pluck and exotic shotmaking - not least in managing to win a point by first getting to a seemingly impossible net cord, then returning Nadal's through-the-legs shot - earned him warm support from the crowd, as well as several chances to break Nadal. But on the key points the world number two was always untouchable as he earned a fourth round clash against Japan's Kei Nishikori. Nishikori shrugged off injury problems during a comfortable 6-4 6-2 win over the Czech Republic's Lukas Rosol. Despite having to receive treatment for a foot niggle, the Japanese player booked his place in the last 16 in a shade over an hour's play. Gilles Simon set up a last-16 showdown with Andy Murray after weathering a back problem to defeat Jurgen Melzer 7-6 6-4, while Tomas Berdych suffered a shock against Grigor Dimitrov in Miami. The number 13 seed took an injury time-out shortly before racing into a five-point advantage in the opening set tie-break, eventually holding off the Austrian 7-5. And the Frenchman held off the pain better than Melzer could hold off his growing frustration during the match, recovering from a break in his serve early in the second set to double-break en route to the match. Murray had received a walk-over into the fourth round after Canada's Milos Raonic pulled out of their round-of-32 tie hours <b>...</b>