Roger Federer beats Kei Nishikori to reach Australian Open quarter-finals

Roger Federer cast off doubts about his fitness by winning a five-set thriller with Kei Nishikori to reach the Australian Open quarter-finals.

This was only Federer's fourth official match since returning from six months out with injury but the Swiss stayed tough on Rod Laver Arena to win 6-7 (4/7) 6-4 6-1 4-6 6-3 in three hours and 24 minutes.