Fifth-seed David Nalbandian reached the last four of the Rome Masters with an impressive 6-4, 6-3 win over Vincent Spadea of the U.S. on Friday.

He now meets 2002 French Open winner Albert Costa, who beat the Czech Republic's Jiri Novak 6-4, 6-2 in an earlier match.

The Argentine, who finished runner-up at Wimbledon two years ago and is the highest ranked player left in the claycourt tournament, had enjoyed a straight-sets win over Spadea in their only previous meeting in last year's Masters Series event in Montreal.

He quickly took charge, varying the pace and direction of his groundstrokes to break in the third game and wrap up the first set.

Spadea returned aggressively to gain a break at the beginning of the second set and race to a 3-0 lead.

"It was so tough right then," said Nalbandian. "The wind was making me serve not so good and I think that's when Spadea put in his best games. If I had gone down 4-0 it would have been difficult."

Nalbandian, however, rallied to pull the break back in the fifth game, and then took advantage of unforced errors in the seventh and ninth to break twice more and reel off six straight games.

"I'm not playing my best tennis," said the Argentine, who missed Masters Series events in Indian Wells and Miami in March because of an ankle injury.

"But I'm happy to be in the semi-final and I'll try to do better (in the semi-final against Costa) tomorrow."

Costa, who knocked out world number one Roger Federer in the second round, proved too consistent for Novak and reached the last four in Rome for the third time in his career.