Japan's Kei Nishikori reached the French Open last 16 for the seventh time on Friday when Swiss opponent Henri Laaksonen retired with a leg injury in their third round clash.

Nishikori had taken the first set 7-5 when the Swiss qualifier quit.

The 31-year-old Nishikori had needed more than eight hours and two five-setters to get to the third round.

On Friday, however, he was on court for just under an hour as he goes on to meet either German sixth seed Alexander Zverev or Laslo Djere of Serbia for a place in the quarter-finals.