Starter Tomo Ohka gave up two hits and struck out two in two innings before Dan Smith, Darwin Cubillan and Matt Blank combined for five hitless innings. Julio Manon gave up an RBI single to Gary Matthews Jr. in the sixth for the Mets' lone run.
Guerrero's blast off starter Dicky Gonzalez staked Montreal to a 2-0 lead in the top of the first. The game remained a pitchers' duel into the eighth, when the Expos erupted for four runs off Pat Strange.
Alex Andreopoulous, a backup catcher, wsa two for two with a double and two RBI for Montreal.
2014: NFL Cheerleaders [PHOTOS]
Michael Sam cut from the Dallas Cowboys