During the first half of yesterday's Major League Soccer playoff game at RFK Stadium, D.C. United presented a clinic in passing the ball. It went from the head of one player to another to another and another. The Columbus Crew's players were left firmly planted on earth, looking up to observe a game played above their heads. Aerial acrobatics in a circus could hardly be better.

In the first half, and especially the first 15 minutes, United's players were interchangeable in excellence. When one gave up the ball to a teammate, he replicated the dexterity with a clever run or pinpoint pass of his own. It was as if Placido Domingo were singing several parts.

Needless to add, Game 1 of the best-of-three Eastern Conference playoffs was destined to be D.C. United's. "When the playoffs come around, that's the time to turn it up," said slender midfielder John Maessner, who assisted on the second goal in a 2-1 decision. "This team definitely does that."

It was a Yankee-like performance.

D.C. United had played a dull game in wrapping up Miami and the first round of playoffs. Uncharacteristically, the local lads last week looked to be settling for a 0-0 score and a shootout victory, which they got. Not so yesterday. They came to play as good teams do when the games are critical. Thomas Rongen, United's first-year coach, had the team ready mentally for an all-out effort.

"We haven't had the luxury of training for a full week," he said. "Having seven days to focus on this game showed today. We had a lot of energy from the opening whistle. We talked about that. We certainly wanted to be the aggressor at home. Everyone played the way we wanted to play."

How often can a coach say that?

D.C. United's dominance was rewarded from a likely pair, Marco Etcheverry and Jaime Moreno. No one has more playoff assists in MLS's four seasons than Etcheverry. And during that time, Moreno has the most playoff points (goals and assists). Surprise! Etcheverry assisted and Moreno scored United's first goal. Such artists. But you must see the finished work. This goal merits being called a highlight.

Eddie Pope was a crucial third party in the score. The defender stepped up to the near post to settle under Etcheverry's corner kick. Then, while lifted off the ground, Pope flicked his head and reversed the ball toward the far post. There, Moreno merely tapped it into the net. He had an ocean of net in front of him.

D.C. United appeared to be running downhill the entire first half, but that, of course, was an illusion. After the teams reversed directions for the second half, United still seemed to be running downhill. "The work rate of this team today might have been the best of all games," Rongen said.

From the defenders forward, United pushed Columbus relentlessly. It took four outstanding efforts by Crew goalkeeper Mark Dougherty and a couple of defenders to keep the score from being an outlandish 5-0. Finally, from out of the back came the relentless Jeff Agoos with a pass to Maessner, whose cross met midfielder Ben Olsen 12 yards in front of the net. The ball hadn't touched the ground when Olsen extended his foot and fired a fast shot past Dougherty.

Seventy-two minutes had gone by, the best 72 for United. Lapses in concentration and Columbus's desperation attack resulted in a goal and several other chances that were too close to satisfy a United team that had played so well. "It was disappointing because we wanted to get a clean sheet," Rongen said. It might be to his advantage in preparing his players this week for Game 2 in Columbus next Sunday that they did not give him a whole game that was almost perfect. With the score and the scares, Columbus left its card.

"The thing about them in particular is, you have to watch them for 90 minutes," Pope said. "They're always there. They're hard to defend."

"We can still do better, I think," Rongen said. But it would seem all his players can do would be to maintain their effort for the whole game. Pope and Carey Talley on defense stifled the Crew's talented forwards, Brian McBride and Stern John. Pope might have been the best on the field. Columbus certainly had no playmaker to rival Etcheverry.

This is no time to quibble about the last minutes. D.C. United sustained a beautiful rhythm for most of the afternoon, camouflaging its hard work so that it looked like play.

"Everyone was sharp," Pope said. "Everyone was ready to go."

"I'm definitely going to watch the game tape," Maessner said.

This was the 12th straight time that United has defeated Columbus at RFK. Tom Fitzgerald, the Crew's coach, expressed sentiments you would expect: exasperation and determination. He mentioned nothing about "the law of averages." He made no excuses. He praised United. "As I've said before, the road to the championship goes through D.C. and if we're going to get there, we've got to beat them here. We win at home, we get a chance to come back and try again. That's what sports is all about."