Seventeen-time Grand Slam champion Roger Federer continued his remarkable return from injury as he booked his place in the quarter-finals of the season-opening Australian Open after fending off Japan's Kei Nishikori in a five-set thriller here on Sunday.
The Swiss maestro, who was out of action for six months due to a knee injury, emphatically quashed doubts about his fitness by overhauling fifth-seed Nishikori 6-7 (4-7), 6-4, 6-1, 4-6, 6-3 in a high-octane fourth-round contest that lasted three hours and 24 minutes on Rod Laver Arena.
Federer, who reached his 13th Australian Open quarter-finals, will now lock horns with Germany's Mischa Zverev, who stunned world number one Andy Murray 7-5, 5-7, 6-2, 6-4 in the fourth-round contest that lasted more than three and a half hour.