Gaston Gaudio of Argentina, a claycourt specialist, showed his ability on hard courts by defeating fifth seed Kafelnikov 6-4 6-1.

Their defeats leaves Australian Lleyton Hewitt with a smoother path to the final.

Hewitt, the number seven seed, bucked the trend, with a comfortable 6-3 6-3 victory over Ecuador's Nicolas Lapentti.

The Australian number one and 12th seed Juan Carlos Ferrero are the only seeds left in the bottom half of the men's draw.

Hewitt now faces French veteran Fabrice Santoro, who used some smart shots to overcome Argentine junior Guillermo Coria 6-2 7-5.

But the day belonged to Roddick. "I give him full credit," Sampras said. "He really played great, with no fear. He's serving consistently in the 130s (mph) and making them. That's pretty tough to play against.

"The way he played, the future of American tennis definitely looks good,"

Roddick said: "That's the first top 10 player I have beaten. He is probably the greatest player of all time. So I made a statement to myself."

Roddick will meet Andrei Pavel of Romania, who himself created an upset by beating 15th seed Frenchman Sebastien Grosjean - a finalist here two years ago - 7-6 (7/2) 2-6 6-0.