Roger Federer faces Philipp Kohlschreiber in the first match of the evening session on Arthur Ashe Stadium. Don Emmert / AFP
Roger Federer faces Philipp Kohlschreiber in the first match of the evening session on Arthur Ashe Stadium. Don Emmert / AFP

Nadal and Federer back in action as semi-final clash nears: US Open order of play - Day 8