It doesn't seem to matter what the circumstance is, the Mets seem to never panic. I've made some mention in prior years about how the Mets have had players who always keep a cool head in big situations (good examples include Endy Chavez, Damion Easley and Fernando Tatis, at least some of the time). This particular Mets team appears to be comprised almost entirely of Don't Panic guys. So when their best pitcher comes out against a fierce rival without his best stuff, the Mets don't panic. Scott Hairston hits a Home Run, David Wright hits a Home Run, and down by a run in the 9th, the Mets just toyed around with Jonathan Papelbon, doing everything necessary to push across the 2 runs needed to win the game.
Ultimately, David Wright will wear the heroes' mantel, since he not only got the winning hit, but also drove in 3 additional runs prior to that hit. But how about Ike Davis, who took a Papelbon offering and inside-outed it to left field for the leadoff double? How about Jordany Valdespin showing some patience with 2 outs, working the count full before getting hit by a pitch? How about Ruben Tejada, who seems to see upwards of 5 pitches every time he steps in the batters box, working out an 8-pitch walk? And who can forget Daniel Murphy, who fell behind 0-2 before nailing a pitch off Papelbon's leg that managed to bounce just far enough away for him to not be able to do anything with it. Josh Thole laid down a great sacrifice in there as well. Even Kirk Nieuwenhuis, who's been scuffling and injured, battled before striking out.
The point is, just as complacency can be contagious, and can sink a team that's not mentally tough enough, so can remaining calm in high pressure spots spread around a team as well, and in the case of the Mets, it's made them a better, cohesive unit. It helps, and is perhaps the difference between the 2012 Mets and, say, the 2010 Mets that were hovering over .500 at the All Star Break as well, that this is a team comprised less of veterans and reclamation projects, and more of young, heady players trying to make names for themselves. The familiarity they have with each other has made them a more cohesive unit with similar approaches to the game, and to the situation, and to the at-bat. The end result is that you have a 9th inning like we had tonight, where it seemed like everyone went up there determined to do something. And, ultimately, they did.