The bloop hit with two outs and runners on second and third ended a frigid doubleheader at Coors Field that was scheduled after Monday's game was snowed out.
Carlos Gonzalez raced home with the winning run, giving Colorado a sweep of Tuesday's games. The Rockies won the first game 8-4.
Pacheco and Yorvit Torrealba both had two RBI in the game. Rafael Betencourt (1-0) notched the victory with a scoreless 10th in which he walked two batters but struck out one.
The Mets led 7-1 in the top of the fifth but Colorado roared back with four runs in their half of the inning to stay in contention.