"I'd give all the credit to Mario Lemieux," said a dejected Al Iafrate. "Period. Exclamation point."

It was that simple for the Pittsburgh Penguins. It was that heartbreaking for the Washington Capitals.

Having lost control of a playoff series to Lemieux and the Penguins, the Capitals last night were left to deal with the stunning finality of a 3-1 defeat that ended a regular season of great accomplishment and left the team frustrated once more in the playoffs.

"It's real disappointing to lose the series — it's how we lost," said Don Beaupre, once more outstanding in goal. "We had them three games to one. The fifth game, we didn't play like we wanted to put them away and it really hurt us in the end. We let them up. We didn't put them away."

In that critical game, the Capitals were lackluster and lost at home, 5-2. It gave the Penguins hope. "After the fifth game," said Penguins Coach Scotty Bowman, "I think the team felt we were going to come back for a seventh game. And sometimes visiting teams win."

Once again the Capitals failed to win a game in May.

For the second straight year, the Capitals were victimized by the Penguins.

Once more they failed to stop a playoff skid.

It hurt all the more because in the regular season, as they outdistanced Pittsburgh handily in the Patrick Division standings, the Capitals won the series, 5-2. They converted 22 percent on the power play in the regular season series compared with 9.5 percent for Pittsburgh. Beaupre even recorded a shutout; his opposite number, Tom Barrasso, went 1-4.

But Lemieux, the NHL's leading regular-season scorer, stepped up his scoring tempo in the playoffs — 17 points in six games after missing the first game with a shoulder injury. In the playoffs it was Pittsburgh's power play that had the electricity.

"It comes down to fundamentals — penalty killing and the power play," said Dino Ciccarelli, slumped motionless into his locker stall, almost whispering. "We did that great all year. . . . "

But not in the playoffs that determine the Stanley Cup winner and by which a season usually is measured. The Capitals had never finished as high as second overall in the NHL. Yet they're familiar with playoff heartbreak.

"It's tough to stand up here and face the music after leading the series three to one," said Coach Terry Murray. "I never thought we'd be in this situation.

"That was the kind of game I wished we had in Games 5 and 6," added Murray. "I wish we had given this effort in Game 5 and Game 6. I think it would have given us a better chance to win."

A chance, not a certainty. Because of Lemieux. "We were beaten by Lemieux," Murray said. "He's a very special person."

Lemieux sparked the Penguins' special teams once more, opening the scoring with a shorthanded goal and assisting on Jaromir Jagr's game-winner after Iafrate's goal.

"They adjusted," said Ciccarelli. "Both teams didn't get as many chances as they did in the first four or five games. When you get in a series that is 3-1, 3-2, everything tightens up. . . .

"Even when it was 3-1 we knew it was going to be a tough battle. We didn't get overconfident or anything of that sort. We tried to stay focused and stick to our game plan. Obviously I wish it hadn't come to this."

"They had more reason to be tight than we did," said Iafrate. "I mean, they won the Stanley Cup. Not being able to repeat, or not even coming close to repeating would be worse than being a team who had a really good year and was up 3-1 on the Stanley Cup champs."

But the Penguins fought back calmly as Washington slept.

"We couldn't leave the season after the loss in the fourth game," said Bowman. "It was an important game for the franchise. I think the whole team felt that way. The fifth game was the key game."