Juan Martin del Potro stuns Roger Federer in US Open quarter-finals

Juan Martin del Potro has moved to within one win of a second US Open final after a stunning four-set victory over Roger Federer at Flushing Meadows.

The 2009 winner overcame illness and a two-set deficit to defeat Dominic Thiem in the last 16, and the Argentine was the clear underdog against Federer, who was attempting to set up a last-four showdown with Rafael Nadal.

However, a fine performance from Del Potro - combined with a below-par showing from his Swiss opponent - resulted in the 28-year-old running out the winner by a 7-5 3-6 7-6 6-4 scoreline.

There were just five break points in the night-session encounter on Arthur Ashe Stadium, but it was Del Potro who looked the more assured on the big points as he registered a second US Open triumph over Federer after their classic match in the final eight years ago.

Del Potro will now try to complete a famous double when Nadal stands in his way on Friday, with the winner going on to face either Pablo Carreno Busta or Kevin Anderson.