Marchand applies the dagger as Bruins put Leafs on the brink

Brad Marchand scored the go-ahead goal in the second period and Tuukka Rask made 31 saves as the Boston Bruins defeated the Toronto Maple Leafs 3-1 on Thursday to grab a commanding 3-1 lead in their first-round playoff series.

Torey Krug and Jake DeBrusk had the other goals for the Bruins, who can wrap up the Eastern Conference quarter-final when they host Game 5 on Saturday at Boston's TD Garden. David Pastrnak added two assists.

Game 6, if necessary, would be played Monday back at Air Canada Centre.

Tomas Plekanec replied for the Leafs, who got 18 stops from Frederik Andersen.

Patrice Bergeron, part of a top line that combined for 20 points in the Bruins' two emphatic home victories to open the series, was a surprise late scratch with an upper-body injury. Riley Nash took his spot between Marchand and Pastrnak.

Marchand breaks tie

Marchand snapped a 1-1 tie for Boston with 3:05 left in the second after the Bruins were whistled for icing. Leafs head coach Mike Babcock put his top line, centred by Auston Matthews, out hoping to pounce on a tired group, but Nash won the draw to Adam McQuaid, whose clearing attempt up the boards skipped past Toronto defenceman Jake Gardiner.

Pastrnak moved in on a 2-on-1 with Marchand, faking a shot to draw the over-aggressive Nikita Zaitsev to him before feeding his linemate with a slick pass for a wide-open net.

The Leafs had a number of chances earlier in the period to push ahead — including a Mitch Marner breakaway off a stretch pass from Morgan Rielly that Rask turned aside with the blocker — but were unable to get one by Rask.

Boston then made it 3-1 at 4:17 of the third on another bad Toronto pinch. David Krejci blocked Travis Dermott's shot and raced the other way on a 2-on-1 before finding DeBrusk, who beat a helpless Andersen after Roman Polak failed to block the pass across.

No room for speedy Leafs

The speedy Leafs found their legs and space through the neutral zone in their 4-2 victory in Game 3 on Monday, but found it tough to find room against the Bruins again.

Pastrnak now has 11 points in the series (four goals, seven assists), while Marchand has seven (two goals, five assists) despite Boston's top line getting shut out in Game 3.

The visitors stunned the Leafs just 28 second into the game to quiet an electric Air Canada Centre when Krug's snapshot from the sideboards found its way past Nash and Plekanec in front before glancing in off Andersen's shoulder.

Toronto eventually got going and tied the score at 7:43 when Marner fed a pass from his knees that was helped on by Patrick Marleau to Plekanec, who made no mistake over Rask's blocker for his first goal since being acquired from Montreal prior to the trade deadline.

The Leafs kept coming and nearly grabbed the lead later in the period, but Rask shot out his pad to deny Zach Hyman from in close as Toronto outshot Boston 12-7 through the opening 20 minutes.