The U.S. Olympic Festival opened its doors to the Soviet Union today, and the result was splendid, judging from the three standing ovations given by a Summit crowd of 5,940 to Olympic ice dancing bronze medalists Marina Klimova and Sergei Ponomarenko.

After the U.S. brother-sister team of Natalie and Wayne Seybold put on a sparkling performance to win the festival gold medal in pairs figure skating, the Soviet husband-wife team gave a seven-minute performance and was called back for two encores by the crowd.

"We've been going through serious preparation," Klimova said through an interpreter, "so this was a nice holiday."

The vacation included a Texas barbecue later in the afternoon with some U.S. athletes and Soviet boxers and cyclists, who also will participate in exhibitions this week.

After the last encore, which included a bit of tango, Natalie Seybold skated onto the ice with cake, and a woman led the crowd in singing "Happy Birthday" to Klimova, who turned 20 today.

The two Russians had been scheduled to come to the United States since mid-June. So even though the other Soviet figure skaters who were scheduled to come withdrew, Klimova and Ponomarenko were allowed to attend. They will remain in the United States until Aug. 10, taking in an ice show in Colorado and training with Carlo Fossi, who coached Dorothy Hamill, among others.

The Seybolds -- who finished third in the U.S. nationals and eighth in the world championships -- were in near-perfect sync, placing first in the scoring of all seven judges. Katy Keeley of San Diego and Joe Mero of Costa Mesa, Calif., who were fifth in the U.S. nationals, finished second. Fifteen-year-old Kristi Yamaguchi of Fremont, Calif., and 16-year-old Rudy Galindo of San Jose won the bronze.

The Seybolds, who grew up in Marion, Ind., have been training in Wilmington, Del., but will soon move to Newark, Del., because the University of Delaware is going to allow them to use the ice rink at more favorable times.

"We've been having to train at night -- till three in the morning," Wayne Seybold said of the situation in Wilmington.

They have had their moments of tension, but they say their relationship has become smoother in recent years.

"Now, it's not that hard," said Natalie Seybold, 20. "When we were younger, we were going through stages where we were fighting. We might not have made it without our parents, and we only moved out of the house two years ago. But we don't live together now, and we meet each other to skate. Now, we're like best friends."

Wayne Seybold, 22, said that they have kept skating from dominating their lives.

"I'm going to be taking a few college classes, and Natalie may in the spring," he said. "Debi Thomas the women's world champion, who will be a sophomore at Stanford this fall has set a good trend in that skating is almost secondary. If there are other things in your life, it takes a lot of pressure and anxiety off."

Christopher Bowman, of Van Nuys, Calif., won the men's figure skating title, with Paul Wylie of Denver second and Angelo D'Agostino of Colorado Springs third. World champion Brian Boitano, who withdrew last Monday because of an injury to his right knee, was the favorite in the event.

Jill Trenary, who finished fifth in the U.S. nationals, won the long program to capture the women's figure skating competition. going into tonight's final free skate. Cindy Bortz of Tarzana, Calif., was second and Tonya Harding of Portland, Ore., won the bronze.