Sixth seed Andy Roddick overcame 14th seed Tommy Robredo in a fierce centre court battle 6-3, 4-6, 7-6 at the Rome Masters here on Friday.
It's the second time the hard court specialist has reached the semi-finals of this competition following his appearance at the same stage in 2002.
It was Roddick's eighth win in as many matches against Robredo, although the Spaniard did claim a set for the first time.
The sixth seed will meet Stanislas Warinka in the next round after the Swiss ousted eighth seed James Blake in three sets.
Roddick won the first set on a single break but despite many chances and lots of pressure on the Spaniards serve, he could not do likewise in the second.
Robredo's forehand was regualrly ripping past Roddick at the net but the American was not letting himself be discouraged from advancing.
However in the 10th game of the second set he was beaten by another scorching Robredo forehand to give up the break and the set.
No sooner had he got back on level terms, though, Robredo immediately played a poor service game at the start of the second and he missed an easy inside-out forehand to give the sixth seed the upper hand again.
But Roddick could not hold onto it for very long and double-faulted on break point at 3-2 to keep Robredo's hopes alive.
Thereafter the American was under more pressure as Robredo held serve easily but in the final set tie-break Roddick earned a mini-break in the first point.
He held on after that and finished the set and the match in style with a smash.
