For anyone that thinks Celtics fans have become complacent after last year’s title, I have one request: get yourself to the TD Banknorth Garden for a playoff game as soon as possible.

All the recent talk about Celtics fans accepting the fact that their beloved Green wouldn’t be able to defend Banner 17 without superstar forward Kevin Garnett had me thinking that perhaps Bostonians had gone soft. That all changed when I walked into the Garden for Game 2 of the opening round of the 2009 playoffs against the Chicago Bulls. The place was buzzing, from 20 minutes prior to tip off to 20 minutes after Ray Allen drained the winning three with 2.0 seconds left.

Boston fans are left in a familiar – and preferred – position as underdogs. The media has been chief source of that opinion, citing undoubtedly Garnett’s absence and a championship hangover as the main reasons that the Cleveland Cavaliers will be the eventual Eastern Conference champs.

As is the Boston fan custom, Celtics fans easily identified a villain in the Bulls lineup – and it was a usual suspect. Joakim Noah tussled with Celtics center/beast Kendrick Perkins, which was a bad move. Perkins physically dominated Noah for a loose ball, before flexing in the former Florida forward’s face. This was all the Garden faithful needed to keep a consistent rain of epithets and chants (“No-ah sucks!”) going for all four quarters. Sometimes, a little hatred for an opponent goes a long way in motivating a team. Seated in the balcony section (for a $40 Craigslist-purchased ticket; the face value was $35), I had the pleasure – and (auditory) misfortune – of sitting a row in front of foreign C’s fans, who treated the game like it was a soccer match. From waving a strange and unidentifiable flag (whose nation might not even play basketball) to urging the section to chant with them (“Ev-ary bod-eeee…let’s go Setz-Kos!”), these dudes were undoubtedly psyched for a game that didn’t even have title implications – yet.

Fans were not just frenzied during Garnett’s pre-game primal Jumbotron screen scream, or when the same video display urged fans to get “Garden level” loud on the suspiciously-measured Noise meter. They stayed up and loud during momentum swings on both sides, at the end of the half and even during TV timeouts. It didn’t hurt, of course, that fans were treated to a fourth quarter duel-for-the-ages between Ben Gordon and Allen. But the point is that the fans were already in full chaos mode before the former UConn stars put on their own show.

The party wasn’t just limited to the Garden, however. The bars littered around the North End were also full of fans drunk on victorious spirit, as well as spirits themselves. I ended up at The Greatest Bar on Friend Street and it was packed with fans reliving the look on Noah’s face as Allen hoisted the winning shot over his face, or Garnett’s scream toward the Chicago bench at time expired (a lip-reading offers the translation of “That’s right, motherf&*@ers!”). Booze and good feelings were free flowing, as well as a few unsportsmanlike insults hurled outside the bar aimed at fearful people in Bulls jerseys trying to get away from the arena.

While the Celtics may or may not be in trouble on the court as they navigate the Cavalier and Magic-infested waters of the Eastern Conference playoffs, one thing they can count on is the Garden being a definite home-court advantage. With Garnett (and now Leon Powe) out, they’re going to need someone to continue to step up, and it’s not just Glen “Big Baby” Davis or Mikki Moore. The “sixth man” element the crowd offers will be alive and well, surrounding the prized parquet in the playoffs.