Martina Navratilova ended Tracy Austin's four-year winning streak at the $125,000 Grand Prix tournament in Filderstadt, West Germany, with a 6-3, 6-3 victory in a match that took 90 minutes.

Navratilova's game never reached the peak of previous matches she played this week. But she still was too good for Austin, 19, who had made this tournament her own and had beaten Navratilova for the title in 1979 and 1981.

Navratilova, given the choice between $22,000 prize money and a new Porsche sports car from the sponsors, picked the car without hesitation. "I know I can afford to buy the car myself, but it's nice to be able to get it in this way," she said.

Navratilova powered through to love-40 in the fifth game of the decisive set, clinching the game two points later with a backhand down the line and holding serve to go ahead, 4-2. She muffed a chance for 5-2, but broke Austin again in the ninth game on her third match point.

In Vienna, top-seeded Brian Gottfried lived up to his ranking by routing Bill Scanlon, 6-1, 6-4, 6-0, to capture the $100,000 Volvo Grand Prix tournament.

In Tokyo, Jimmy Arias beat Dominique Bedel, 6-2, 2-6, 6-4, to win the $175,000 Japan Open.

Wojtek Fibak won the $300,000 Dutch international WCT tournament in Amsterdam by defeating Kevin Curran, 7-5, 3-6, 6-4, 6-3.

At Salisbury, Md., Kate Mills and Ginger Gorman of George Washington University defeated Diane Ventura and Diane DeVries of Rutgers, 3-6, 7-6, 6-1, to win the doubles championship of the Salisbury State Intercollegiate tennis tournament. Lee Custer of James Madison defeated Cathi Giordano of George Washington, 6-4, 6-1, in the singles final.

James Madison won the team title in the three-day tournament with 34 points, followed by George Washington, 29 1/2, and Richmond 25.