Fabio Fognini of Italy puts away a volley against Rafael Nadal of Spain during their match on the fifth day of the 2015 US Open Tennis Championship at the USTA National Tennis Center in Flushing Meadows, New York, USA, 04 September 2015. The US Open runs through 13 September, which is a return to a 14-day schedule EPA/JOHN G. MABANGLO

Rafael Nadal of Spain follows through with a serve against Fabio Fognini of Italy during their match on the fifth day of the 2015 US Open Tennis Championship at the USTA National Tennis Center in Flushing Meadows, New York, USA, 04 September 2015. The US Open runs through 13 September, which is a return to a 14-day schedule EPA/JOHN G. MABANGLO

Fabio Fognini of Italy hits a return against Rafael Nadal of Spain during their match on the fifth day of the 2015 US Open Tennis Championship at the USTA National Tennis Center in Flushing Meadows, New York, USA, 04 September 2015. The US Open runs through 13 September, which is a return to a 14-day schedule EPA/JOHN G. MABANGLO

Rafael Nadal of Spain hits a return against Fabio Fognini of Italy during their match on the fifth day of the 2015 US Open Tennis Championship at the USTA National Tennis Center in Flushing Meadows, New York, USA, 04 September 2015. The US Open runs through 13 September, which is a return to a 14-day schedule EPA/JOHN G. MABANGLO

Rafael Nadal of Spain reacts after winning a point against Fabio Fognini of Italy during their match on the fifth day of the 2015 US Open Tennis Championship at the USTA National Tennis Center in Flushing Meadows, New York, USA, 04 September 2015. The US Open runs through 13 September, which is a return to a 14-day schedule EPA/JOHN G. MABANGLO

Fabio Fognini of Italy reacts after breaking serve from Rafael Nadal of Spain during their match on the fifth day of the 2015 US Open Tennis Championship at the USTA National Tennis Center in Flushing Meadows, New York, USA, 04 September 2015. The US Open runs through 13 September, which is a return to a 14-day schedule EPA/JOHN G. MABANGLO