Vitas Gerulaitis advanced to the final of the $300,000 South African Open in Johannesburg with a 3-6, 6-1, 6-4 victory over Andres Gomes of Ecuador.

Gerulaitis will play today against top-seeded Guillermo Vilas, who beat South African Kevin Curren, 7-5, 6-3. Curren reached the semifinals with a 6-2, 6-4 upset of third-seeded Jose-Luis Clerc.

Gerulaitis played erratically throughout the match, losing the first set to Gomes when the Ecuadorean placed shots all over the court. But Gerulaitis, a resident of Kings Point, N.Y., recovered in the second set to break Gomes' serve twice . . .

In Sydney, top-seeded Martina Navratilova defeated Evonne Cawley 6-0, 3-6, 6-1 to capture the $125 New South Wales Open tennis tournament.

Navratilova received $22 to bring her total career earnings to $4.6 million. The capacity 8,000 gallery fans switched their weeklong partisan allegiance from Cawley and chanted for Navratilova as she stopped Cawley with deep volleys and powerful drives.

Cawley had stunned Andrea Jaeger, 4-6, 6-1, 6-4, to to get into the final.

Navratilova, the top-ranked player in the world, had some trouble in the other semifinal with lighty regarded American Zina Garrison. But Navratilova came away a 7-6, 6-2 winner.