The team's offense looked to be unstoppable after it eliminated the Ottawa Senators in the second round with a 13-5 scoring advantage in the final two games of the series.
But in a stunning turn of events, the stingy Boston defense and the brilliant play of star goaltender Tuukka Rask have completely shut down one of the deepest and most talented groups of forwards that the NHL has seen in many years through the first two games of the conference finals.
Following a great Game 1 performance in which the Bruins became the first team to shut out the Penguins since Feb. 1 of 2012, Boston took the second matchup with a clinical 6-1 victory after jumping out to a quick 3-0 first-period lead.
As a result of their failure to protect home ice, the Penguins will travel to Boston down 0-2 for Wednesday's Game 3 in TD Garden, where the Bruins are 21-7-3 this year (regular season and playoffs combined).
The list of problems for the Penguins to address at practice is a lengthy one, and the most shocking surprises through two games have been the ineffectiveness of the team's power play and lack of offensive production from its top forwards.
The greatest concern for the Penguins is that captain Sidney Crosby, widely considered the world's best player, has been held scoreless in back-to-back playoff games for the first time since the final two games of last year's first-round series defeat to the rival Philadelphia Flyers.
In addition to his scoring struggles, the superstar forward has a minus-three rating, only six shots and a faceoff percentage below 40 percent through two games.
Crosby also had four giveaways in Game 2, which was twice the number that the Bruins had as a team. His first giveaway allowed Boston winger Brad Marchand to have a breakaway and score 28 seconds into the game, the quickest goal of the 2013 playoffs. Poor puck possession is very rarely an issue for No. 87 because of his great hands, superb puck-handling skills and composure with the puck.
Crosby also has to find a way to be successful when reigning Frank J. Selke Trophy winner and elite defensive forward Patrice Bergeron is on the ice defending him. Bergeron is creating turnovers, playing physical with Crosby and frustrating him on nearly every shift. The Bruins center has also dominated Crosby in the faceoff circle, where he ranks second in the playoffs with a 63.6 win percentage on draws.
In fact, the entire Bergeron line was dominant against whoever was on the ice with them in Game 2 (photo via @ShutdownLine):
The Bergeron-versus-Crosby matchup is one that Pittsburgh must win to avoid a sweep, but with Boston having the last line change as the home team in the next two games, getting Crosby away from Bergeron is going to be a tough challenge for head coach Dan Bylsma.
Per Corey Sznajder of ShutdownLine:
As a captain and a leader, Crosby's effort and lack of passion on the ice was very discouraging for the Penguins. He did not set a great example for his teammates with his performance or body language. Pittsburgh will not win this series without a much better effort and performance from Crosby on Wednesday, but he also needs his star teammates to improve their games.
Here are some notable stats from Pittsburgh's top six forwards over the first two games.
No team is going to win when its best players make no impact offensively and fail to play quality defense in their own end. The Bruins' top line has totally outplayed its Penguins counterparts. Boston's top trio of David Krejci, Nathan Horton and Milan Lucic led the way with three goals combined in Game 1 and scored or assisted on two more in Monday's win.
The play of Evgeni Malkin in Game 2 was really disappointing from the Penguins' perspective. The reigning Hart Trophy winner's effort level has been poor throughout this series, especially defensively with his inconsistent backchecking and lack of aggressiveness in his own end.
Bruins defenseman Zdeno Chara, who is playing like a Norris Trophy winner during the playoffs, has won his matchup with the Russian center through two games, which is one reason why the Penguins have failed to generate enough offense. Per TSN's Stat Guy:
Speaking of the Norris Trophy, Penguins defenseman Kris Letang, selected as a finalist for the award this season, has gone from a dominant player in the first two rounds to one of the team's most disappointing players in the East Final.
Letang has been scoreless in two straight games for the first time in this year's playoffs. He also has a minus-five rating against the Bruins thus far. As TSN points out, Letang has been on the ice for a lot of Pittsburgh's goals against in the postseason.
Defensive breakdowns have been a common occurrence in this series for the Penguins, and against a four-line team like the Bruins, these mistakes will continue to hurt Pittsburgh. Letang has been involved in quite a few of these breakdowns, including Krejci's second goal in Game 1 when he interfered with his own goalie and Nathan Horton's goal in Game 2 when he failed to clear the puck.
Letang and Matt Niskanen, who are the Penguins' top two blueliners, failed to record a single hit despite getting 23:06 and 17:07 of ice time in Game 2, respectively. The struggles of Crosby and Malkin will dominate headlines, but the lackluster performance from Letang is really hurting the Penguins. As the team's No. 1 defenseman, zero points and awful defense in two games is unacceptable for a player of his caliber.
Pittsburgh's power play has also been ineffective versus Boston, which is a bit surprising since the Penguins led the playoffs in goals scored with the man advantage (13) entering this series. The Bruins are blocking shots, breaking up passes with active sticks and playing aggressively on the penalty kill, which has resulted in the Penguins failing to capitalize on all six of their power-play chances in the East Final.
As for the goaltending situation, Bylsma decided to pull starter Tomas Vokoun in Game 2 when the Bruins took a 3-0 lead 16:31 into the first period. Franchise netminder Marc-Andre Fleury, who Bylsma benched after his struggles in the first round, gave up a confidence-deflating goal when he failed to stop a Brad Marchand shot high on the glove side just seconds after the Penguins got some momentum from a Brandon Sutter goal.
Vokoun should not have been pulled because the team's defense was the primary reason why it trailed 3-0. He deserves to start Game 3, especially after his defensemen gave him absolutely no help in Game 2.
The Bruins beat the Penguins at their own game on Monday. Boston controlled possession of the puck, capitalized on scoring chances, dominated the neutral zone and played with great speed and energy.
This is a Pittsburgh team with a wealth of Stanley Cup-winning experience and more skill than every team remaining in the playoffs. However, the major surprise isn't that the Penguins are down 2-0, because in all fairness, the Bruins are an elite team and capable of beating quality opponents on the road.
The main problem for Pittsburgh is the way that it has lost the first two games. Very rarely do we see the Penguins play with so much impatience when handling the puck, in addition to the team's best players making no impact offensively.
For a well-coached team with a roster mostly made up of veteran players, the Penguins' 0-2 series deficit and inability to protect home ice has been quite surprising.
The Bruins are playing their best hockey of the season and will have a maximum of five opportunities to win two more games against the Penguins and reach the Stanley Cup Final, with three of those games scheduled to be played on home ice.
For Penguins fans who like to remain positive after losses, their team did lead the East in road wins during the regular season, but its chances of winning Game 3 and Game 4 in Boston are slim judging by Monday's performance.
Unless the Penguins greatly improve at both ends of the ice, Boston will push them to the brink of elimination with a Game 3 victory. This improvement has to start with a better performance from Crosby and the rest of Pittsburgh's superstar players who understand what it takes to win in the playoffs.
We will learn a lot about this Penguins team at TD Garden on Wednesday in its first must-win game of 2013.
Nicholas Goss is an NHL Lead Writer at Bleacher Report. Nick was a credentialed reporter at the 2011 Stanley Cup Final and 2012 NHL playoffs, and he is also a credentialed writer at the 2013 NHL playoffs in Boston.