It didn't take long to lose three seeded players in the $175,000 Washington Star International tennis tournament yesterday.

Sixty-one minutes after the first round began in the sauna known as the Rock Creek Tennis Stadium, 12th seed Pat DuPre was eliminated, the victim of a 6-3, 6-1 rout by Ramesh Krishnan of India, one of the rising players in the world.

Tenth-seeded Manuel Orantes and 16th-seeded Marty Riessen quickly followed DuPre to the sidelines, each losing as igonominiously as Dupre.

Orantes, once one of the top three players in the world but now ranked 21st, repeated his first-round embarassment of last year. French left-hander Christophe Freyss beat him, 6-3, 3-4, yesterday.

Riessen succumbed quickly in the stifling humidity, dropping a 6-1 first set to Alvaro Betancur of Columbia, then defaulting. Australia's Brad Drewett also was downed by the heat, quitting while down, 0-3 in the third set, to Rick Meyer.

Only 12 of the scheduled 19 matches were completed as a violent lightning and thunderstorm wiped out the evening matches. They are rescheduled for 11 a.m. today. Second-seeded Harold Solomon was leading Syd Ball, 5-3, when play was stopped. The rain didn't come soon enough for Orantes, Riessen and DuPre.

DuPre, a Wimbledon semifinalist a year ago, has been bothered by a bad back this season and only returned to tournament play last month. But it appeared to be the stifling heat and Kirshnan's backboard-like ground game which bothered him most yesterday.

The court temperature was 110 degrees when the match began at noon, and it was clear that stamina was going to be a factor.

"In this kind of heat winning the first set is doubly important," said Kirshnan, 19, who has moved from 179th to 80th in the Association of Tennis Professionals computer ranks the weather was a major topic of discussion from the minute the first ball was hit.

Corrado Barazzutti, the 13th seed, playing this year. "When you lose the first set you know you'll have to go three to win. That makes you feel tired quickly."

That appeared to be the case with DuPre. After trying to take control of the net in the first set, he stayed back more in the second. From the back court, he was no match for the steady Kirshnan, who did not appear to be bothered by the heat.

As is always the case in this tournament, here for the first time, breezed to a relatively easy 6-3, 6-3 win over Australian Geoff Masters, then said, "I don't think I play here again.

"It is the heat," he said. "I think it is worse here than anywhere. I was in Italy playing Davis Cup until last Sunday. Then I came here. It's just terrible out there."

Despite the heat, the Barazzutti-Masters match produced some good tennis. Barazzutti, Italy's "Little Soldier," is strictly a back court player. Like most of his countrymen, Masters, a quarterfinalist here last year, likes to attack. Barazzutti countered with a number of winners on passing shots.

The first three-set match of the tournament was between two unseeded players, Mike Cahill and Terry Rocavert, the Australian who took John McEnroe to five sets at Wimbledon.

Rocavert, after being trounced, 6-2, in a 21-minute first set, reversed form, ignored the heat and beat Cahill, 6-3, 6-3, the last two sets. The second three-set match was played by a pair of Australians, with Ross Case coming back to beat David Carter, 4-6, 7-5, 6-1.

The most entertaining match of the afternoon featured 18-year-old University of Tennessee sophomore Rodney Harmon and qualifier Roberto Vizcaino of Spain. Harmon, from Richmond, is a good serve-and-volley player who is woefully weak on ground strokes.

Even on the slow clay he dominated Vizcaino on serve throughout the match. But he wasted a chance to break Vizcaino at 4-4 in the first set, botching three forehands, starting at 0-40. Vizcaino went on to win that set, 7-6, in a 7-3 tie breaker.

The two cruised along on serve until 4-4 in the second set. Then Harmon's stomach began to bother him. He lost his serve for the first time and Vizcaino served out the match.

"When I got to 4-4 in the first and had him 40-0 on his serve I started rushing things, trying to play too fast." said Harmon, one of a handful of solid black players. "By the second set I thought I was going to die because of my stomach. Maybe it was the tension. I don't know."

Mario Martinez, Bolivia's best player, was disqualified yesterday afternoon when he failed to appear for his match with George Hardie. His spot was taken by David Siegler . . . Top seed Jimmy Connors will play his first match tonight, against Tim Wilkison . . . Gene Mayer and Eddie Dibbs, the third and fourth seeds who played the final in the U.S. Pro championships (Dibbs won) play their first matches today.