Del Potro through to last eight as Thiem retires hurt

Updated: 

Dominic Thiem's US Open campaign is over after he retired hurt in his last-16 clash with Juan Martin del Potro because of a knee injury.

The eighth seed was handed a tricky tie against the 2009 champion at Flushing Meadows, who took the opening set 6-3.

Thiem's movement appeared extremely hampered and he opted to call it a day trailing 3-2 in the second set.

Del Potro progresses to the quarter-finals of a grand slam for the first time since his run to the semi-finals of Wimbledon in 2013.

He will face the winner of the match between third seed Stan Wawrinka and Illya Marchenko in the last eight.