The eight-time Grand Slam winner Agassi was the defending Los Angeles champion, and he also captured the title in 1998, 2001, and 2002. He was runner-up in 1988 and 1999.

Gonzalez needed one hour, 53 minutes to win 6-4, 3-6, 7-5 over Agassi, who is retiring after next month's US Open.

"I am at peace with my career," Agassi said. "I feel great about the decision to retire and I look forward to the summer."

The 36-year-old American survived three match points in the third set, but couldn't hold serve in the final game as Gonzalez clinched the victory with a backhand winner.

"It was a high standard match," said Agassi, who received a long ovation as he walked off the University of California at Los Angeles courts for the last time. "He stepped it up at the end of the game with some pretty spectacular shots. It is a disappointing loss for me."

Gonzalez, of Chile, won their only other meeting 3-6, 6-4, 7-6 (7/5) in Washington in 2003.

Ironically, Gonzalez helped lower the curtain on another American tennis legend's career.

Gonzalez beat Michael Chang 6-3, 7-5, 5-7, 6-4 in the first round of Chang's final match at the 2003 US Open. Chang retired after the Open.

"It is a pleasure and honour for me to play against Andre," said Gonzalez, who turns 26 on Saturday. "He is 10 years older than me, so I grew up watching him play Pete Sampras and Boris Becker. He is still motivated and still competes like he did 15 years ago."

The bronze medallist in singles from the 2004 Athens Olympics advances to the semis where he will face No. 8 Dmitry Tursunov of Russia, who won in a walkover over top seed Andy Roddick.

The other Saturday semifinal will see sixth seeded Tommy Haas square off against Slovakia's Dominik Hrbaty.

"He absolutely murdered some shots," Agassi said of Gonzalez. "He changes the pace well and mixes up his serve a lot.

"I hung in there. I just wasn't getting enough looks on points on his serve.

"I might have been able to get a little more aggressive and taken a few more chances."

Agassi, who was playing in just his second quarterfinal of the year, announced in June at Wimbledon that he would retire after the US Open, which starts in August.

"You never prepare yourself for the emotions of the moment," Agassi said. "It is not just the game you are leaving but it is the people you share the experience with.

"It is like a business. And you stop doing that business and working with these people. It is like I am having to say goodbye on two fronts."

With temperatures hitting a scorching 43 degrees C (110 degrees F) on the court, Agassi withered in the final two games of the match. But he blamed the loss more on his mistakes and Gonzalez's strong game.

"The heat of his forehand was more of a factor," deadpanned Agassi.

Gonzalez rallied in the ninth game of the third set to hold serve. Down 15-40, he fought off two service break points by firing a forehand winner and then an ace as he jumped out to a 5-4 lead.

Gonzalez has seven career ATP titles with his most recent coming last year in Basel, Switzerland.

Most of tennis' big names have passed on the Los Angeles hardcourt tournament. The 32-player draw featured just two players Lleyton Hewitt (13th) and Roddick (10th) who are ranked in the top 15 in the world and they are both gone.

Top seed Roddick pulled out of the tournament with an side injury just hours before a Friday quarterfinal match against Tursunov.

Roddick first suffered the left side strain during his 6-7 (3/7), 6-3, 6-2 second round win over wild card Scott Oudsema.

"It is really disappointing," Roddick said.

This was Roddick's first tournament under the guidance of his new coach, Hall of Famer Jimmy Connors.

Roddick, who is known for his explosive serves and competitive spirit, is hoping that by hiring Connors, he will shake his "one slam wonder" label.

Roddick captured the 2003 US Open title but he has not won a major since. He is winless on the ATP Tour in 2006.

Germany's Haas defeated Paul Goldstein 6-3, 6-4 in another quarterfinal match on Friday.

Haas said the loss on Friday of fifth seed Agassi and Roddick increases his chances of winning his third ATP title in 2006.

Second seed Hewitt was eliminated in the first round meaning, leaving Gonzalez as the lone player who is seeded in the top five.

"The door has opened up a bit," said Haas, who won the 2004 Los Angeles event. "Other guys will take the opportunity and try to jump on it."

Hrbaty booked the final semifinal spot with a 7-6 (7/0), 6-2 win over American Robby Ginepri in the night match.