WASHINGTON -- Top seed Andre Agassi was made to work hard before reaching the semifinals of the Legg Mason Classic with a tough 6-7 7-6 6-3 victory over Sweden's Thomas Enqvist on Friday.

"I served for the first (set) and he served for the second, and it was just one of those nights where it happened to be going my way," Agassi said. "I just tried to make him play well ... and I was just interested in making him make great shots to win it."

The American's victory evened their lifetime score at 4-4.

Agassi will now face number six seed James Blake after the 22-year-old former Harvard University student beat Spain's fourth-seeded Alex Corretja 6-4 6-4.

It is the second time this year Blake has defeated Corretja.

He also won their first-round encounter at the Australian Open.

In other matches, Thailand's Paradorn Srichaphan, who upset Agassi in the second round at Wimbledon this year, continued his giant-killing run at the Washington event with a 6-3 7-5 victory over eighth-seeded Finn Jarkko Nieminen, Reuters reported.

Srichaphan, who knocked out third seed and last year's beaten finalist, Sjeng Schalken of the Netherlands, in the third round on Thursday, said that victory had given him confidence.

"After my win yesterday against Schalken I said to myself today that I'm just going on the court and have fun," Srichaphan told reporters.

He now meets fifth seed Marcelo Rios, who was granted a wild card for the event, in the other semifinal. Rios beat 16th-seed Fernando Meligeni of Brazil 3-6 6-4 7-5.

Meligeni, who had never beaten Rios in their previous four meetings, upset defending champion Andy Roddick in the third round.

Despite their history, Rios said he had struggled against the Brazilian. "The first two sets I didn't play well on the important games but I played well on my service games when I was down," the former world number one said "Once I got my chances to break (his serve) I did it pretty well especially when I was down 3-5 in the third set."