Jonathan Toews carried the puck down left wing and dished a cross-ice pass to Seabrook, who fired in a shot from the right circle before goalie Steve Mason could slide across the crease.
Patrick Sharp and Bryan Bickell scored 59 seconds apart late in the second period, and Viktor Stalberg also connected in regulation for Chicago (18-0-3), which won its eighth straight overall and has earned 39 out of a possible 42 points this season.
We don't have any excuses tonight. Excuses are for losers. We've played with five defensemen before and it didn't affect us. We just had a bad second period and it cost us the game. We have to look in the mirror and blame ourselves.
— Bruins coach Claude Julien on his team's play with the loss of defenseman Johnny Boychuk