Bobby Carpenter arrived at the mouth of the goal just as the puck did. He dipped his stick, changing the angle of his teammate's shot just slightly -- but just enough for it to zoom past the sprawling goalie. In the twinkling of an eye, the Washington Capitals had taken a 4-3 lead over the New Jersey Devils.

His game-winning goal scored, his balance having been upset by a New Jersey defenseman, Carpenter lay face down and eyes closed on the Capital Centre ice. About 10 feet away, between a shield of glass, a bearded 40-year-old public relations executive in row A of section 101 was shouting "Way to go, Bobbeeeeee!" His name was Steve Mehlman, and without him there might not have been any Capitals this season, much less cheers.

Nine month ago, Steve Mehlman was one of about a dozen loyal fans who decided that big league hockey should not vanish from the local scene, as major league baseball and soccer had before it and as the Capitals were threatening to do. So Mehlman became a founding director of the Save the Caps Committee.

Fans like Mehlman have tried to save foundering teams in other cities. Usually, the effort attracts as much attention as a fly on the haunches of an elephant. The owner is too busy watching the bottom line. The media have other fish to fry. The only person who gains is the guy who prints up the committee's stationery.

Not so here. Mehlman and Company sold season's tickets over the phone. They badgered businessmen for help. They turned up on most of the talk shows. And they helped carry the day. When Capitals owner Abe Pollin announced last June that he would stay in business for at least one more year, he pointed to the accomplishments of Mehlman's committee as a major reason.

Now, the 1982-3 Caps' season that Mehlman helped make possible is dwindling down. The post-season playoffs begin in a couple of weeks, and for the first time, the Capitals will be part of them. As Mehlman likes to point out, he hasn't just helped save a hockey team; he has helped save a winner.

"I believe that sports rubs off," Mehlman said between periods last Thursday night. "I think that the success of one team helps other teams. And it helps the city. It isn't just dollars and cents. Look what the Redskins did for this city. That wasn't just a matter of dollars and cents."

Mehlman has been a Capitals season's ticket holder "since Day One." His two front-row seats cost him $1,000 a season. Add to that $80 for 40 games worth of parking and the $15-per-person pre-game dinners he often eats at the Capital Club, and Mehlman's investment in hockey is considerable.

Is the kick he gets equally considerable? "Oh, yes," says Mehlamn. "Look around you. Look at all these people. whatever happens on the ice, I get satisfaction in here, watching the team do well and watching people enjoy them."

Mehlman's loyalty to the Capitals borders on obsession. Every year, he and his family spend a few days at the Capitals' pre-season training camp in Hershey, Pa. Manyh nights, Mehlman will fiddle with a radio at his home in Crofton, trying to pick up broadcasts of Capitals games when the team is playing in the Northeast or Midwest.

Once, while in Florida on business, Mehlman unaccountably picked up a Capitals broadcast on the radio of his rent-a-car. To keep the signal from facing, he drove back and forth between two interstate highway exits for an entire evening.

In the long run, Mehlman is just the kind of fan the Capitals need to attract if they plan to survive. He followed the Rangers while growing up in the New York area. He played the game only once -- "kids on a pond. I was the goalie. I got knocked out by a shot." Yet he discovered once he moved to Washington as an adult that he missed it. "To me," he says, "it has been worth the money."

Very few in Thursday night's crowd realized who Steve Mehlman was. None of the fans applauded. None offered thanks.

Yet, as the Capitals finish their most successful season, Mehlman says he has a nice warm feeling. "I really do," he said. "It's good to succeed. It's good for the fans. It's good for the whole city."