Marchand's tally in the second period forged a 1-1 tie and Boston went on to win its second straight to start the season.
Torey Krug contributed a goal and an assist, while Zdeno Chara and Jordan Caron each scored for the Bruins.
Jimmy Howard stopped 33-of-37 shots for Detroit, which fell for the first time in three games.
2014: The Year in Fashion [PHOTOS]
LeBron James reveals his new Nike shoes