John LeBoutillier, as Tip O'Neill knows well, goes at his opponents teeth bared and claws out. In fact, the New York Republican representative says he lost 15 pounds in preparation for last night's 21st annual baseball clash between congressional Democrats and Republicans.

From the moment he showed up in his New York Yankee uniform at Four Mile Run Park in Alexandria, LeBoutillier could not be restrained. In the dugout he stamped and stormed, berating "lousy" umpiring and his teammates' "deplorable" base-running. On the mound he was no less intense, throwing one beanball and a few brushback pitches to potbellied Democrats. He looked absolutely crestfallen as a New Yorker from across the aisle, Tom Downey, touched him up for a triple to right center.

"Chriiiiist!" he screamed, hurling one of the more printable epithets that came from the players last night. "My God!"

Last year life imitated baseball once again as LeBoutillier led the Republicans to victory in his freshman year in the House. Despite LeBoutillier's continued determination and theatrics, this year's contest was no replay.

Rep. Ronald Mottl (D-Ohio), who recently lost his primary reelection bid and is leaving the House at the end of the year, pitched the Democrats to a 6-4 victory in a game that benefited Children's Hospital. Wearing a Cleveland Indian uniform and sporting a toothbrush-style haircut, Mottl evoked the image of another Indian, "Sudden" Sam MacDowell.

After the first inning, Republican coach and former Florida congressman Lou Frey Jr. analyzed Mottl's pitching: "He throws one fastball every eight pitches. All we have to do is jump on all the slow c---."

But with the help of D.C. Del. Walter Fauntroy's base-running and the clutch hitting of Mike Synar (D-Okla.), Mottl's offspeed best was enough. Catching his breath between innings, the defeated congressmen looked up at the filled bleachers and out toward centerfield and indulged a little welling of nostalgia. "This game means a real lot to me," said Mottl. "I really want to go out a winner. It was embarrassing to lose that primary."

Both sides brought along cheerleaders, the Reaganettes and the Dazzlin' Democratic Darlin's. They were equal in razzmatazz, but the Democratic side certainly outdistanced the stuffy chants of their opposite numbers with their calls of "TWO FOUR SIX EIGHT, WE REMEMBER WATERGATE!"

Enjoying the whole scene from the less frenetic Democratic dugout was Rep. Claude Pepper (D-Fla.), perhaps the only man there who managed to wear long sleeves and not sweat. Clearly, after spending 33 years in the Senate and House, Pepper is a man who knows the meaning of energy conservation.

In fact, he seemed a little worried when his side appeared to be faltering in the middle innings. "You know," he said. "I think the Democrats may have overtrained. They practiced twice."