FOR YEARS John McEnroe screamed and cursed his way through tennis matches, and the craven tennis establishment gave in. Last weekend, in the person of a 22-year-old Australian umpire named Richard Ings, the sport finally grew some self-respect and struck back. For once the parable of the brat had the right ending. It was the best thing that has happened to decent behavior in years.

Doubtless you already know what occurred. Mr. McEnroe was up a set and service break in his third-round U.S. Open match against Slobodan Zivojinovic of Yugoslavia, and serving for the second set at 5-3, when he had what he regarded as several bad calls. He lost the game and his self-control and went into his familiar tirade at the expense of Mr. Ings, who was in the chair.

The officials on whom Mr. McEnroe has heaped such abuse in the past have often been amateurs, local volunteers whom he could bully with impunity. But Mr. Ings turns out to be a professional, one of five full-time umpires now on the tour. He gave Mr. McEnroe a warning, when that didn't work assessed him a penalty point and eventually took away a full game and the set. Under the rules, the next outburst would have cost Mr. McEnroe the match -- and wonder of wonders, he shut up. Deterrence works. He also began to play better tennis, and eventually won. Mr. Zivojinovic applauded him as they came to the net to shake hands. The show of good sportsmanship was jarring in the contrast it provided.

Mr. McEnroe will apparently be suspended for two months. That will interrupt a comeback and could end his career. No one can rejoice in a result like that, but the lesson can only be healthy. Games send messages in the kinds of behavior they tolerate.