Tennis: Nadal downs Nishikori to reach Open quarters

World number one Rafael Nadal fought off a spirited Kei Nishikori to win through to the quarter-finals of the Australian Open on Monday.

Nadal won 7-6 (7/3), 7-5, 7-6 (7/3) in three hours 17 minutes and will play Bulgaria's Grigor Dimitrov in the last eight.