ZAGREB, YUGOSLAVIA, JULY 12 -- Elena Chouchounova swept all four women's gymnastics events tonight as the Soviet Union retained its lead in gold medals at the World University Games.

Chouchounova, 18, has produced six gold medals. On Friday, she was part of the Soviet Union's victory in team competition and also won the all-around individual. Tonight, she was best in the beam, vault, uneven bars and floor exercise.

With 15 golds, the Soviet Union was four ahead of Romania. The United States had five, Hungary four.

This afternoon, swimmer Noemi Lung of Romania won her fourth gold, in the women's 200-meter freestyle.

It was another poor showing for U.S. swimmers. Only the men's 400-meter freestyle relay managed a gold medal, edging the Netherlands by six-hundredths of a second in 3 minutes 23.56 seconds.

In 22 swimming finals, the United States has four golds, one in an individual event.

In a men's basketball quarterfinal, Troy Lewis of Purdue University made two free throws in the final seconds, giving the United States a dramatic 83-82 victory over Spain.

With the United States trailing, 82-81, Lewis was fouled and had three chances to make two shots. He converted the first two.

Saturday night, Perry McDonald of Georgetown scored 18 points to lead the United States to a 98-57 victory over Belgium.