The former world number one, who is recovering from a knee injury, battled hard to dismiss his 27-year-old semi-final opponent, winning 6-3, 6-7, 6-1 in nearly two hours.
Qualifier Michael Russell took advantage of the ailing Mardy Fish for a 6-3, 6-1 victory Thursday in the second round of the U.S. Men's Clay Court Championship.
Former winner Ivo Karlovic continued his domination over German Benjamin Becker, winning 7-5 (7/5), 6-4 in the first round of the US Men's Clay Court Championship on Tuesday.
Somdev Devvvarman began his clay court season with a thumping 6-2 6-1 win over America's Robert Kendrick in the first round of the US Men's Clay Court Championship.
Argentina's Juan Ignacio Chela beat defending champion Lleyton Hewitt of Australia 6-4, 6-3 to reach the semi-finals of the US Men's Clay Court Championships in