NEW YORK, SEPT. 7 -- Pieter Aldrich and Danie Visser of South Africa won the U.S. Open men's doubles title today over surprise finalists David Wheaton and Paul Annacone, the first unseeded team to make a final since 1976. Aldrich and Visser took it in straight sets, 6-2, 7-6 (7-3), 6-2.

Wheaton, 19, and Annacone were playing in only their third event together, but they are an obvious success, winning their debut in Toronto in July and reaching the quarterfinals of an event in New Haven, Conn., earlier this month. They reached the Open final by beating Patrick Galbraith and Kelly Jones, 7-6 (7-3), 7-6 (7-2), 6-7 (2-7), 7-6 (8-6).

But Aldrich and Visser, seeded second and ranked No. 3, took advantage of their rivals' inexperience. Wheaton and Annacone had 12 break-point opportunities and converted none.

Aldrich and Visser had a remarkably easy passage to the championship. They received a default from No. 15 Ken Flach and Robert Seguso in the third round when Flach stormed off the court of a mixed doubles match. By that time all the other seeds in the tournament had lost. Grand Slam Possible

Top-seeded Helena Sukova and Jana Novotna of Czechoslovakia moved nearer a Grand Slam sweep in women's doubles when they routinely defeated third-seeded Natalia Zvereva and Larisa Savchenko, 6-2, 6-3.

However, Novotna and Sukova must play No. 3 seeded Martina Navratilova and Gigi Fernandez in the final. Navratilova and Fernandez defeated Kathy Jordan and Elizabeth Smylie in a grudge match of a semifinal, 6-4, 7-5.