The tennis world, that straight-toothed set which thinks a backboard is 40 feet wide, was predictably unsettled by John McEnroe's angry outburst in Friday's Wimbledon semifinal against Jimmy Connors.

McEnroe, it seems, drilled one of his booming southpaw serves past a flatfooted Connors. The T.V. cameras clearly showed that the ball landed well within the prescribed box, but, inexplicably, the serve was termed a fault. Young McEnroe (who but two years ago was Young Upstart McEnroe) struck the hallowed Centre Court grass with his racket and stormed to the sidelines, unwilling to continue lest the rest of his future efforts meet with similar results. At first, the man in the high chair tried reason; "Mr. McEnroe will resume play," he intoned. When that failed, he turned to humiliation. "This is a public warning," he informed Mr. McEnroe, right to his face and in front of 18,000 at Wimbledon and millions more around the world.

The fans were aghast at McEnroe's behavior; they cheered the lifeguard when he ordered the American to return to the court. The next day papers stuck on him, not for the first time, the worst of tennis epithets: "Brat." Even Mr. Connors, who probably tortures insects in his spare time, informed Mr. McEnroe that he was upset. "Shut your mouth and play," he advised. It seems tennis players, like everyone else from Westchester, are supposed to be well-behaved. Confronted with raw broccoli hors d'oeuvres, it is regarded as impolite to make faces.

This preppie code applies, thank God, to few other sports. Americans, and the kind of Britishers who attend soccer matches realize that when men congregate in short pants it is to compete, and, that competition involves a certain diminution of one's gentility. All basketball players--all basketball players--complain when they think an unjustified foul has been called, and many complain on principle, every time they hear a whistle. The thought of Mendy Rudolph bellowing, "Mr. Dawkins will resume play." The idea of the Garden scoreboard operator announcing to the assembled throng, "Mr. Tiny Archibald has been issued a public warning." The next time Don Zimmer charges out of the dugout, consider how effective Larry Barnett would be were he to say "One word more and I will issue a public condemnation."

No other sport demands such politeness of its practitioners, except perhaps golf. And who could get excited enough to shout obscenities on a golf course? Stock car racers don't have to use turn signals, and they're allowed to pass on the left as well as the right. Hockey players are permitted to check opponents without first issuing a caution. In short, the other games men play have rules, but they do not have an ethic of etiquette.

Thankfully, the blue-blood code dominating tennis is slowly fading. "Rude" players are still contemptuously labelled brattish, but there are many more brats than before--as well there should be, if being a brat means pointing out when the officials are fouling up great and exciting matches with incompetence. It is even all right, it seems to me, to get mad at an opponent; in other sports, this is called "psyching up" and encouraged, but in tennis it is called ungentlemanly. Those Americans who realize that a backboard is but three feet wide will never love the sport as long as it remains corseted in the tight Victorian discomfort of false politeness.

"Mr. Dave the Hammer Schultz has received a public caution. Mr. Dave the Hammer Schultz will resume play."