Brad Marchand had a goal and two assists for the Bruins (37-17-9), who are 10-0-4 in their past 14 games and have won eight of their past nine. Boston leads the Toronto Maple Leafs by three points for second in the Atlantic Division.
Defenseman Erik Karlsson didn't play in the third period because of injury for the Sharks (37-19-8), who finished a four-game trip 2-2-0. San Jose trails the Calgary Flames by five points for first in the Pacific Division.
WATCH: [All Sharks vs. Bruins highlights]
There was no update on Karlsson's status after the game. He missed the Sharks' previous game, a 5-3 win at the Detroit Red Wings on Sunday, because of a groin injury after leaving in the second period of San Jose's 4-0 loss at the Columbus Blue Jackets on Saturday. He missed nine games with the injury before returning Feb. 16.
"Well sure, anytime somebody gets hurt there's regret [about playing him]," Sharks coach Peter DeBoer said, "but I really don't know -- same injury, different injury? I have no idea what we're dealing with yet. I can't even make that call."
Logan Couture gave San Jose a 1-0 lead with a power-play goal at 12:47 of the first period. He stole Zdeno Chara's pass from behind the net and stuffed the puck under Jaroslav Halak's right pad.
David Krejci, who had a goal and an assist, tied it 1-1 with a power-play goal, scoring on a one-timer from just above the left face-off dot at 14:39.