Boston got second-period goals from Nathan Horton and rising star Torey Krug to build an early lead. Tyler Seguin's first of the playoffs put the Bruins back on top 3-2 in the third.
Only three teams have lost a series after leading 3-0, but the Bruins are the most recent to do it in 2010 against Philadelphia.
The Bruins made the most of another power play and took a 3-2 lead just 2 seconds after a goalie interference penalty against Ryan McDonagh expired. Seguin got to his own rebound in close and shoved a shot past Lundqvist at 8:06 for his first goal of the playoffs.
However, the Rangers still wouldn't go away and they finally connected on the power play as Boyle took a pass from Stepan in the slot and snapped a drive that nestled into the middle of the net at 10:00.
The Bruins used their power play to grab control in the second period, connecting twice in a span of 3:02 to take a 2-0 lead. After Newbury was sent off for goalie interference, when he knocked down Rask, Horton got the scoring going. The Boston forward tried to feed a pass from the bottom of the left circle into the slot, but the puck hit Rangers defenseman Michael Del Zotto and bounced back to Horton. This time, Horton let a shot go that struck the inside of Lundqvist's left leg and caromed into the net at 4:39.
Del Zotto took an interference penalty 1:25 after Boston took the lead, and Krug made the Rangers pay again. Krug, a rookie defenseman who made his NHL postseason debut in the series opener, fired a slap shot from the Stanley Cup logo in the Rangers' zone that sailed past Lundqvist and into the top right corner at 7:41.
However, New York got a big break just 54 seconds later to cut the deficit in half. As the Rangers were moving the puck up ice, Rask stumbled in the crease and fell at around the same time that Hagelin was backhanding a shot on net. Sliding as slowly as possible, the puck eluded Rask as he tried to recover in time to stop it.