Tuukka Rask knew how potent the Penguins offense was. He also knew he could shut them out. "Every game starts with zero," the Bruins poised goalie said, "so you have a chance." And two games ended with a zero for Pittsburgh as Boston completed a sweep with a 1-0 win on Friday night that sent it to its second Stanley Cup final, and maybe its second championship, in three years with a 4-0 series victory. The Bruins will play the winner of the Western Conference finals. The Chicago Blackhawks lead the Los Angeles Kings 3-1 and can wrap it up Saturday night. Rask's second shutout of the Eastern Conference finals continued his domination of the highest scoring team in the NHL. The Penguins big offensive threats - Sidney Crosby, Evgeni Malkin, Jarome Iginla and James Neal - didn't score a single point and Boston outscored Pittsburgh 12-2. "We knew we had to be at our best to beat this team," Bruins coach Claude Julien said. That's exactly what happened. Rask stopped 134 of 136 shots by a team that averaged 4.27 goals a game in its first two playoff series. The few rebounds Rask allowed throughout the series were quickly cleared away by a defenseman or a forward getting back into the play. On offense and defense, the Bruins always seemed to be in the right spot at the right time. They made precise passes and got their sticks in the way of many passes the Penguins tried. In the clincher, all the Bruins needed was one goal and defenseman Adam McQuaid provided it with a 45-foot slap shot from the right that went over goalie Tomas Vokoun's right arm at 5:01 of the third period. Of Boston's 50 playoff goals, 15 have been scored by defensemen. "I think first and foremost, we're obviously trying to be solid defensively," said McQuaid, who had one goal in 32 regular-season games but two in the playoffs. Rask provided the final flourish when he gloved Iginla's hard 40-foot shot as the final buzzer sounded. They were outplayed for much of regulation in Game 3. But they improved after that and won 2-1 on Patrice Bergeron's goal at 15:19 of the second overtime. On Friday night, Boston's Milan Lucic admitted, "We were a little sluggish the first two periods ... and we said, 'We have to win a period to win a series.'"