LOS ANGELES [Sunday]-With a display of power and grace that astounded even those who are used to his dazzling performances, Greg Louganis won his second gold medal of these Olympic Games today, taking the men’s 10-meter platform competition with a world-record score of 710.91 points. He became the first platform diver to break the 700-point plateau, eclipsing the 688.05 he accumulated in preliminaries yesterday. That score broke a year-old record of 687.90 that was his.

“You want your best performance to come in the Olympic Games,” said the 24- year-old Californian. Louganis’s gold medal today also was the 81st for the United States in these Games, breaking the record of 80 achieved by the United States in 1904 and by the Soviet Union in 1980.

Repeatedly asked to compare the achievements of Louganis to those of Carl Lewis, the runner and long jumper who won four gold medals here, Ron O’Brien, who coached the United States diving team, said, “Greg’s two golds are equal to Carl Lewis’s four, maybe even better. You have to put it in perspective and look how dominant he is.” Louganis, who also won the 3-meter springboard gold medal Wednesday, is so superior to everyone else in his sport that he not only makes every dive look beautiful, but he makes the most frightening dives look almost effortless.

His final dive, a reverse three-and-a-half somersault, is the same maneuver that killed the Russian Sergei Shalibashvili last summer at the World University Games, when he flung his head back to execute the first somersault and hit it on the platform. Louganis seems to stretch his talents to the fullest when the pressure is greatest-pressure he puts on himself when his competitors aren’t close enough to push him. Before his 10th and final dive, he said he was very nervous, even though he had virtually clinched the gold medal.

“You want to hit 10 good dives, you can’t let up at any time, you can’t play safe,” he said. “I was scared going into the last dive. But I stood there and told myself that no matter what I do here, my mother will still love me. That thought gives you a lot of strength.”

He also said that he sings to himself on the platform in the waiting moments just before each dive. “It’s usually √ęBelieve in Yourself’ from √ęThe Wiz’ that I sing,” said Louganis, who has studied dance since he was less than 2 years old, and earned his undergraduate degree in drama from the University of California at Irvine. “You’re up there 33 feet above the water, with not a whole lot on, and seven people judging you, and it’s a very vulnerable position. You’ve got to have a lot of confidence in yourself.”