A Georgetown University law professor and his wife were held up by two men armed with handguns on a Georgetown street last night but their assailants fled after the professor struggled with one of them in an attempt to save his credit cards and a gun went off.

Willy Schlieder, a German citizen who was a senior official in the European Common Market, suffered only a knee scratch in the shooting. "My leg is still aching," he said. "But I'm happy to be alive."

Schlieder, 55, said he and his wife Ursula, both dressed in expensive furs, were walking down 30th Street shortly after 8 p.m. on their way to the Kennedy Center when the two men approached from behind and pulled them apart.

One man pushed Mrs. Schlieder to one side and, holding his gun at her forehead, tried to grab her mink coat and handbag. She resisted. "She was yelling . . . in German, she said 'you pigs! you pigs!' " Schlieder said.

The second man demanded Schlieder's wallet. Schlieder took it out but asked that he be allowed to keep his credit cards. "He said, 'I want your credit cards.' And I said, 'You won't have them.' "

The two began grappling and the robber tried to get Schlieder's coat. Schlieder shouted to his wife to surrender her things. His assailant's gun discharged, apparently accidentally.

"We were happy the shot got off," Schlieder joked last night. "We saved our coats. If not, they were going to undress us."

The two men then fled to a large car parked across the street and sped away with their lights off. They took with them Mrs. Schlieder's purse, Schlieder's wallet and a luxury fur hat that he said he had bought many years ago in Norway.