The Washington Star International Tennis Tournament, which is missing the top three players in the world to begin with, lost its defending champion, ninth-seeded Brian Gottfried, and second-seeded Gene Mayer, No. 5 in the world, in startling first-round upsets yesterday.

Gottfried eliminated himself with at least two dozen unforced errors in a straight-set, 7-5, 6-3, loss to unseeded, unheard-of Angel Giminez.

Mayer suffered cramps in the third set in losing an entertaining match to Czechoslovakian Stanislov Birner, 4-6, 6-4, 6-4.

Heavy rains forced postponement of all six evening matches, including the featured matches, Jaime Fillol of Chile against Harold Solomon, and Eddie Dibbs against Steve Kurlevitz. The postponed matches will begin today at 11 a.m.

The Grand Masters singles and doubles finals also were postponed. The singles will be played at 7 o'clock this evening; the doubles still await re-scheduling.

Birner barely survived the weekend qualifying round and, when he looked at the draw sheet, he figured he would be playing only one match in the $200,000 event this week.

"When I saw I was playing Mayer I decided to risk it all," Birner said yesterday. "I didn't have anything to lose." So Birner, ranked 134th in the world, gambled and won key points with low-percentage shots.

Mayer, who hasn't played a tournament since the French Open because of an injured wrist, won the first set after trailing, 3-1. But he lost the second set and suffered a cramp in his right leg at 2-3 in the third set. At that point, Mayer could not sit down during breaks on the sideline.

Mayer held serve twice to tie the final set, 4-4. But with Birner leading, 5-4, and Mayer serving to avoid elimination, a second cramp, this one in the groin, struck Mayer and limited him to a poor limp.

Mayer actually started the game well. He took a 15-0 lead with a forehand cross court, but couldn't handle a shot and the game was tied, 15-15. On the next point, Mayer hit a drop shot that Birner slapped back for a winner, making it 15-30.

As Mayer walked back to serve he almost stumbled. He was clearly in pain and took nearly a minute to try to walk the cramp out. When it was obvious that the cramp would not subside, Mayer served anyway. Birner returned serve, and Mayer netted the ball. With double match point against him and cramps refusing to let him move, Mayer served at 15-40.

Birner returned again, and Mayer hit the ball wide. Birner advanced to the second round.

Mayer has a history of cramping, particularly in the sort of stifling heat he faced yesterday. But he said afterward he had done everything possible to make sure cramps wouldn't bother him during this tournament.

"I've been training in New York for the past few weeks," Mayer said. "It was 95 degrees and 95 percent humidity there, too; typical, lousy New York-Washington summer. But I wasn't tired. . . I had been taking vitamins, minerals, electrolyte replacements, everything under the sun.

"I could probably play again in another hour. Just normal cramps," Mayer said with frustration, as he paced the interview area in an attempt to let his leg muscles relax. "I hope you folks don't mind talking to a moving target."

A healthy and in-the-groove Mayer is a formidable foe. But after an eight-week layoff, he had trouble getting into this match. Mayer admitted playing the key points poorly and not pressuring Birner as he should.

He missed at least seven or eight drop shots and was suckered by Birner several times by return drops and winners off short balls. "Birner hit excellent drops and touch shots," Mayer said. "It all seemed to be working."

But the key to Birner's success in the second and third sets was his ability to harness a usually erratic serve. "He was confident," Mayer said. "In general, he's a poor server. But today, he served very well. In the times I've seen him, his serve has never been impressive."

But twice in the third set, at 3-3, and 4-4, Birner, won the lead games on four straight points set up by hard, well-placed first serves. It helped that Birner was serving into a gusting, 20 mph wind.

"I took risks on everything; drop shots, ground strokes, serves," said Birner, a member of the Czech Davis Cup team. "It was my best win since I defeated Stan Smith in the French in 1978." Birner said he began drop-shotting Mayer to set up passing shots.

"He's better playing from the base line," Birner said. "So I tried to bring him in to the net as often as possible."

There, Birner could take advantage of Mayer's two-fisted attack from both sides. Mayer can get better control of his shots with two hands, but it limits his reach significantly. Even on the ground strokes, Birner consistently aimed shots at the lines, forcing Mayer to extend himself.

Birner also did something else correctly. To guard against cramps he rubbed his legs with alcohol whenever possible.

When a reporter told the 5-foot-4 Giminez she had never heard his name, he replied: "You haven't heard my name? That's because you haven't been reading the newspapers," he joked.

He said he has played every summer in Europe. "I could make more money and more points. The tournaments over there are more easy. I was playing pretty good early this year, so I decided to come to the United States this summer."

Giminez hit excellent passing shots when Gottfried followed his serve in, and won five of the first six games in the second set.

In afternoon play, five players were fined for inappropriate conduct. The largest was against Gilles Moretton, who was fined $250 for "verbal abuse" of referee Anthony Rene during a loss to Nick Saviano.