Frenchman Gael Monfils is through to the semi-final stage of the Legg Mason Tennis Classic in Washington.
Top seed Monfils saw off sixth seed Janko Tipsarevic 6-4 6-4 in the quarter-finals to advance.
Monfils will now play American John Isner after the 11th seed beat Viktor Troicki 7-6 (7-5) 3-6 6-1.
Donald Young will take on Radek Stepanek in the other semi-final.