This was rock bottom. This was the nadir. This was a Wednesday night in the middle of March that felt like the bottom of the Grand Canyon, that felt like the loneliest spot in the desert. This was Pepsi Center, Denver, Colo., where it felt for all the world like the Knicks’ season had come to die. “Everything happens for a reason,” Tyson Chandler said. In the darkest moments of March 13, it was difficult to understand how that could be possible. Carmelo Anthony’s homecoming had been a disaster; Nuggets fans had bathed him in bile, all but spat on him, and he had spent much of the night looking like Jim Brown dragging himself back to the huddle, his knee a mess, his confidence shot, his game in tatters. And that wasn’t even the bad part. The bad part would come late in the first half when Chandler collided with Corey Brewer, crumpled to the floor, and couldn’t pick himself up – couldn’t put any weight on his left knee, in fact, and had to have himself carried off the floor, all 7-feet-1 of him, by James White and Chris Copeland. If you know a Knicks fan, you know what happened then, and if you know a lot of Knicks fans, you really know what happened then. E-mails started whipping back and forth. Text messages. Phone calls. A small sampling of my own e-mail inbox: “Season over.” “Of course.” “Are you #@$#%$ kidding me?” “#@#$%$#!!!” “@#$%^*#&%$##@!!!!!!!” And so on. “It’s a long season,” Chandler said yesterday, inside a small, empty room on the second floor of the Ritz Carlton Boston Common, smiling and han ding a fruit plate to a Knicks PR man. “Every year you’re reminded of that. But I think we’ve been really reminded of that this year.” As Chandler spoke he admitted that memories of that night in Colorado are fuzzy at best, and there are times it feels like that happened in a different season, a different year … maybe to an entirely different player. But he was certain: that was rock bottom. That was the nadir. There were moments that night — as the Knicks fell to the Nuggets 117-94, two nights after getting hammered 92-63 by the Warriors in Oakland — when it was you started to wonder if they’d ever win another game again. And yet … “And yet,” Chandler said, “here we are.” Here they are, a month and a half later, sitting on the doorstep of their first sweep since the stardust-frosted ’99 team swept the Hawks en rout to the Eastern Conference championship. Here they are. They would lose their next two games after Denver, in Portland and at Los Angeles, the quicksand under their sneakers seemed made of glue.