MUNICH, DEC. 15 -- Brad Gilbert and David Wheaton nearly had a fight today before Gilbert won a five-set battle to reach Sunday's final of the Grand Slam Cup against Pete Sampras.

Before Gilbert advanced, 6-3, 3-6, 7-6 (9-7), 2-6, 6-4, in the $6 million tournament, richest in tennis history, Sampras blitzed Michael Chang, 6-3, 6-4, 6-4, in the all-American semifinals.

The winner gets $2 million and the runner-up $1 million, with today's losers taking home $450,000 each.

The incident between Gilbert and Wheaton occurred after the third-set tiebreaker, following a dispute over a call that went against Gilbert, but was overruled by the chair umpire.

At 6-6 in the tiebreaker, a shot by Gilbert was called out. He screamed in protest, smashing his racket on the net, and did not hear chair umpire Stephen Winyard overrule the call.

Wheaton then protested heatedly, going to the supervisor of officials, Ken Farrar, but the call stood. Wheaton served an ace for 7-7, then double-faulted and Gilbert served out the set.

At the end of the changeover, the players exchanged words, pushed each other and had to be separated by Farrar and other officials. Both were given warnings for unsportsmanlike conduct.

"It was a million-dollar mistake," Wheaton said of the overrule. "There was no way he could be sure."

"You don't overrule a line call on the far side at 6-6 in the tiebreak unless you are absolutely sure," he said.

Wheaton said the incident started when Gilbert went to Farrar because Wheaton's brother, John, had been shouting at the umpire during the changeover and complaining about the decision.

"Brad said something about my brother I didn't like," Wheaton said. "I can't even remember what it was. I told him to withdraw his remarks.

"If he had thrown the first punch, I would have been pretty happy."

"He started crying and whining, like a child, and he got his way," Wheaton said.

Gilbert said he had not heard the umpire overrule the call. He said Wheaton's brother had no business walking around the court complaining about the call.

Both players said the incident happened in the "heat of the moment." Gilbert said Wheaton had apologized after the match and they shook hands at the net.

As for Sampras, he had little trouble. He kept Chang racing from corner to corner with his powerful, deep ground strokes, then rushed the net and scored with volleys. He also served 15 aces.

"It's about the best I've played since the U.S. Open," Sampras said. My serve was going very well. I controlled the game and dictated the play."

Asked if making at least $1 million was special motivation, Sampras said: "Beating Michael was more of a thrill than one million dollars. I'd never beaten him as a pro."

Sampras and Chang have been rivals since they played in an under-10 tournament in California.