FRANKFURT, NOV. 17 -- Andre Agassi upset Boris Becker today, setting up a clash with top-ranked Stefan Edberg for the title at the ATP Tour World Championships.

Agassi served and returned with deadly accuracy to beat Becker, 6-2, 6-4, for his third victory over the German this year and first trip to the ATP final. Agassi had eight aces.

"I don't think I've played better than that," he said. "My serve is becoming more of a weapon every day. I'm stronger and my serve is getting better."

Edberg, the Wimbledon champion and the defending champion, broke Lendl at the start of each set for a 6-4, 6-2 victory.

Playing a nearly perfect serve-and-volley game, he won the first set when Lendl hit the net while trying to play back an Edberg volley.

"The key to beating Lendl is to put pressure on him," Edberg said.

Edberg beat Agassi in three close sets in round-robin play earlier in the tournament, and Agassi said: "I am curious to see of he can do it again."

The title, worth $600,000, will be decided Sunday.

Agassi broke Becker in the very first game and immediately seized control of the match. He lost only three points on his serve in winning the first set.

Becker, ranked second, never found his touch and faced one or more break points in six of his nine service games.

Agassi is in his second straight year-end championship, which pits the top eight players in the world against each other.

Becker failed to appear at the post-match news conference and was fined $1,000, ATP spokesman Richard Evans said.

"He feels he cannot face this ordeal right now," Evans said. "He thinks Agassi played far too well today. He is very tired."

Becker came to the tournament after a 10-day break in which he rested a torn muscle in his left thigh.

Agassi has a chance to become the first American to win the season-ending event since John McEnroe in 1985, when the tournament was known as the Masters.

Edberg is assured of ending the year as the top-ranked player in the world.