Vija Vuskalus is best known in Port Washington for being a very fine dentist. But she’s a footnote in U.S. Open history and made her first visit in years to the National Tennis Center on Monday to celebrate the event’s 50th anniversary.

Back in 1968, Vuskalus was a little-known amateur on the U.S. circuit. For the first Open, when both amateurs and pros were admitted to the event at Forest Hills, Vuskalus was named as an alternate.

As it happened, Billie Jean King’s first-round opponent, Australian Helen Amos, was a no-show. A half-hour before the first Open match in history at the Westside Tennis Club, Vuskalus, relaxing in the lounge, was summoned to be an emergency replacement.

Hence, Vuskalus played the first Open match in history — the event was called the U.S. National Championships before the open era.

“It’s my claim to fame,” Vuskalus told The Post.

She wasn’t exactly supremely prepared, though she had twice played King in doubles. King beat her 6-1, 6-0. Times have changed. By her memory, less than 100 fans populated the stands.

Vuskalus, then 29, also remembers King graciously telling her at the net she had improved since they last met. She hadn’t talked to her since — until Monday, when she paid a visit to the tennis legend.

“I don’t know if she remembers who the heck I am,” Vuskalus said.