It will not be quite like this in the future, but rest assured, there likely will be a future involving these two teams. Last night at TD Garden, the Rangers were putting together one of their most complete games of this early season, but watched a 3-0 lead against the Bruins turn sharply into a 3-3 tie ... turn chaotically into a back-and-forth scoreless overtime ... and turn sublimely into a Rangers 4-3 shootout victory. All of which left most of the 17,565 in attendance gasping for breath and applauding what surely looked to be a gnarly playoff series at its earliest conception. “They’re obviously one of the top teams in the Eastern Conference,” said captain Ryan Callahan, who converted the game-winner in the fourth round of the shootout. “If we want to get to where we want to go, we have to beat the top teams and we consider them right up there.” Coming into the game, the Bruins (8-1-2) had lost just once in regulation, and they were not about to let that fade away. After the Rangers (7-5-0) got ahead on goals from Carl Hagelin, Derek Stepan and Anton Stralman — Scoring depth! Who knew? — the momentum changed on a third-period power play resulting from a borderline Rick Nash hooking call. One second after the Boston power play ended, with just over 11 minutes remaining in the game, David Krejci slipped a rebound passed Henrik Lundqvist. At the time it seemed like just a blemish on what could have been Lundqvist’s first shutout of the season — and one he mightily would have deserved for his dazzling 37-save performance. “You know one goal can change the game,” Lundqvist said afterward from under the Broadway Hat, having allowed one shootout tally, to Brad Marchand. “That’s how hockey works. So when they got the first one, you could just sense how everything turned.” It took a while for that turn to result in more goals, but they came, and in the most heart-wrenching fashion. First, with just over 90 seconds remaining and the Bruins’ net empty, Nathan Horton stuffed in a rebound. That got the Rangers’ blood pressure rising, and it boiled over when Marchand roofed a bad-angle wrister with 43 seconds left.