LOS ANGELES -- Defending champion Andre Agassi advanced to the semifinals of the Mercedes-Benz Cup on Friday but once again needed three tough sets to dispose of fifth seed Gustavo Kuerten 7-6 3-6 6-4.

Agassi, who claimed a similarly difficult three-set semifinal victory over the colorful Brazilian last year, led a parade of Americans into the final four with compatriots Andy Roddick and Jan-Michael Gambill also registering quarterfinal wins.

Roddick, seeded fourth, reached his seventh semifinal of the season with a tidy 6-4 6-4 victory over seventh seeded Belgian Xavier Malisse while Gambill battled past Germany's Nicolas Kiefter 7-5 7-6, reported Reuters.

Eighth seed Max Mirnyi of Belarus was the only non-American to get to the semifinals, taming Frenchman Michael Llodra 6-4 7-6.