The Mets finished their eight-game road trip 2-6.
Right-hander Livan Hernandez (10-6) tossed 7 2/3 innings, scattering seven hits, and allowed just one run to earn the victory.
Montreal (52-50) grabbed an early 2-0 lead against Mets starter Tom Glavine (6-11) after Vladimir Guerrero plated both Jose Macias and Orlando Cabrera with a single into right field.
A Cliff Floyd groundout allowed Jason Phillips to score and cut the lead in half in the fourth, but in the bottom of the sixth Expos first baseman Wil Cordero knocked a two-run homer over the left-field wall for a 4-1 lead.
New York (42-59) threatened in the eighth with two-out hits by Jose Reyes and Jason Phillips that chased Livan Hernandez. Eric Knott entered, walked Cliff Floyd on four pitches to load the bases, but Luis Ayala was able to get Ty Wigginton to groundout to end the frame.
Michael Barrett added a run in eighth for Montreal with an RBI double against Graeme Lloyd.
Veteran left-hander Tom Glavine -- now coming away with just one win in his last eleven starts -- worked seven innings, surrendering eight hits and four runs while walking two and fanning three.
C-1B Jason Phillips singled in the fourth inning to extend his career-high hitting streak to twelve games... C Mike Piazza took live batting practice prior to Wednesday's game for the first time since going on the DL and is planning on a mid-August return... LHP Al Leiter (8-5, 5.47) draws RHP Danny Graves (4-10, 5.59) in the series opener against the Cincinnati Reds on Friday night at Shea Stadium...