Halfway through the Chopin, Norman Krieger tasted defeat. "I felt like quitting," the New York pianist said later, but he continued through pieces by Tchaikovsky, Barber and Prokofiev before retreating backstage, ripping off his bow tie and bursting into obscenities.

"I can play that stuff backwards and forwards," he said, finally. "But when it doesn't go, it doesn't go."

Krieger was a semifinalist in the eighth international Tchaikovsky music competition just starting its final round here, but he did not make the list of finalists, announced early this morning, hours after his performance. "ll I want is to go home now and learn some new music," he said. "I'm exhausted."

Judges eliminated Krieger and 109 other piano contestants, leaving 12 to compete in the finals.

*Ever since Van Cliburn walked away from the first Tchaikovsky competition with a gold medal in 1958, the contest of some of the world's most promising pianists, vocalists, cellists and violinists, held every four years, has occupied a special place in the ambitions of young American musicians. This year Americans have reached the finals of all four competitions.

The two American piano finalists, David Buechner and William Wolfram, are competing against four Soviets, a Frenchman, a Briton, a Bulgarian, a Chinese, a Cuban and a Czech.

Wolfram, a New Yorker and Juilliard graduate, is gearing up for his last stand before the 22-member jury at the Moscow Conservatory Sunday evening.

"So help me God, I'm going to open up and give them everything," he said. "If I can really loosen up I can go somewhere."

Still, he thinks several factors are working against him, including the cultural shock of his first trip in the Soviet Union, the tastes of a jury composed of 14 representatives from Soviet-bloc countries, and the nervous tension lack of sleep that are common side effects of the competition.

"I like playing in an emotional way," Wolfram, 30, said, "but I feel that here they perceive too much of that as weakness."

In an informal assessment of the best players in the competition, Californian Daniel Pollock, the only American piano judge, gave high marks to Wolfram. He has "electricity combined with sensitivity and the ability to ignite a public," Pollock said. But he saved his highest praise for Alexei Sultanov, the 16-year-old Soviet sensation who didn't make the finals. "This is one of the greatest talents I have ever heard," Pollock said. "He has an unbelievable depth of emotion."

Several foreign contestants said that the competition at the Tchaikovsky festival is keener and the conditions far more difficult than at other international event. Krieger and others also said they found it awkward that several Soviet judges were the teachers and coaches of some entrants.