Pastrnak made it 5-1 on a 2-on-1 rush with Nick Foligno at 11:12 of the third period, and Taylor Hall scored from the high slot at 17:57 for the 6-1 final.
Boston outshot Chicago 43-18.
"We're playing well, so we have to be happy with that," Marchand said. "But again, we need to be better and continue to be better. As the season goes on, teams get more dialed in their defensive play and stakes raise a little bit as you get towards the playoffs, so we need to continue to elevate."
NOTES:Pastrnak, Marchand and Bergeron factored in on the same goal for the 88th time, the second-most by a trio in Bruins history behind Ken Hodge, Phil Esposito and Wayne Cashman (103). … Only three defensemen in Bruins history recorded more assists in a game than McAvoy: Bobby Orr (six, Jan. 1, 1973 and five, Dec. 20, 1969), Glen Wesley (five on Oct. 16, 1988) and Ray Bourque (five on Feb, 18, 1990; five on Jan. 2, 1994).