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Penguins captain Sidney Crosby had a much easier time explaining what went wrong for Pittsburgh in the Eastern Conference finals than he did in breaking through against the Boston Bruins' stingy defense.

"We didn't score," Crosby said.

And now the Penguins are headed home.

After Pittsburgh led the NHL in goals during the regular season and finished second in total points, the top-seeded Penguins were eliminated with a 1-0 loss to the Bruins in Game 4 on Friday night.

The defeat capped a stunning sweep by the 2011 Stanley Cup champion Bruins.

"I didn't expect to go out four straight," Crosby said. "But the last couple games, I thought we deserved better. Unfortunately we didn't find a way to regroup after dropping those two at home."

The high-powered Penguins, boasting former MVPs Crosby and Malkin, managed just two goals in the series after averaging nearly 3 1-2 per game during the regular season.

Crosby and Malkin both failed to record a point in the series.

"When you're this close, obviously you want to get to the finals," Crosby said. "You don't get opportunities like this all the time, so yeah, definitely, it's disappointing."

Crosby, though, was adamant about one thing: The Penguins had their opportunities — 136 shots overall — but only two slipped past goalie Tuukka Rask, who stopped 53 in a 2-1, double-overtime Bruins victory in Game 3.

"It wasn't a lack of chances," Crosby said. "You could talk about their defensive play, they're patient, they're a good hockey team, but we had our fair share of opportunities. We either had pucks hop over our sticks or hit posts or didn't execute for different reasons.

"(Rask) is part of it, but there is a number of things we'll look back on and know we could have been better."

Pittsburgh coach Dan Bylsma didn't shy away from crediting Rask.

"There's no question that the performance he put in in this series was elite," he said. "He was the difference in the series, there is no question."

For all their firepower and flashy play, the Penguins couldn't deliver as they had during the regular season and the first two rounds of the playoffs.

They finished the series 0 for 15 on the power play after scoring on 24.7 percent of their advantages during the regular season, and 28.2 percent through the opening two rounds against the New York Islanders and Ottawa Senators.

"Maybe because our power play didn't score a goal. That was the key to the other series that we went in and capitalized on key moments," Pittsburgh forward Chris Kunitz said. "Sometimes we barely generated energy from our bench."

Even more mystifying, was the shutdown of Crosby and Malkin, who combined for 31 points in the first two rounds.

"You try to fight, you try to get through to the net and get rebounds, and sometimes they come to you, sometimes they don't," Crosby said. "Obviously, you score two goals as a team in four games, and personally to go without any points, doesn't sit very well."

It clearly weighed on Malkin, as well.

The Russian star sat slumped over at his stall, his hands covering his face, and his sweaty pads still covering his legs, He accepted his share of the blame.

"We scored two goals in four games. It's not enough," he said. "It is my mistakes that I scored zero goals. It's not good for me."

Penguins goalie Tomas Vokoun, who was pulled after allowing three first-period goals in a 6-1 home loss in Game 2, was shocked at the outcome.

"You go through the season with a team like we had and it's very disappointing," Vokoun said. "It's a tough moment, and unfortunately for Pittsburgh, only one team can win and that's not going to be us."

The Penguins hadn't been swept out of the playoffs since 1979, when they also fell to the Bruins. They had been shut out only twice in their previous 147 games.

Boston blanked them twice in this one-sided, four-game whitewash.

"Our team is a team that considers itself a team capable of winning a Stanley Cup, put together to win a Stanley Cup. That's our expectation from Day One," Bylsma said. "No question, you're going to look at this as a missed opportunity."