When the Knicks had finished off the Game 1 victory over the Boston Celtics on Saturday, when Carmelo Anthony had found his touch down the stretch of a 36-point performance, the Knicks still weren’t fooling themselves. While Anthony had hit every big bucket at the start and again down the stretch, they knew to win in the postseason requires defense. So even after a record-setting defensive effort, the Knicks were left to wonder what happened to their best defensive weapon. Tyson Chandler returned to the lineup Saturday for the start of the playoffs after missing the final six games (and 16 of the last 20) of the season because of a bulging disk in his cervical spine. But he left the game six minutes into the third quarter and never returned, watching from the bench as Kenyon Martin — also just back from injury rehab — took his spot. "I knew I would be rusty," Chandler said after the game. "I knew I would be a little winded. I knew at some point my legs would get the best of me. I just wanted to be out there with my team, try to do some things defensive and get some guys open on the pick-and-roll." Chandler, the 2011-12 NBA Defensive Player of the Year, had no points, five rebounds and three fouls in 20 minutes, but those numbers didn’t tell the whole story of just how little the Knicks got from their defensive anchor. He never was himself, moving cautiously and slowly and allowing the Celtics to slip behind and around him as they cut to the rim. Martin, at 35 years old and coming off a severely sprained left ankle, was far more lively and aggressive. The aggressive part from Martin, the Knicks could expect — and desperately needed. But they need Chandler, too, particularly since Martin’s health has been a question down the stretch of the regular season. The Knicks are hopeful that Chandler was right when he said after the game that conditioning was the problem and not lingering effects of the neck injury. "It won’t take him long," Knicks coach Mike Woodson said in a conference call Sunday, with the team getting a day off before today’s practice. "That was a factor. I could tell the way he was moving that he didn’t have the kind of pop we’re used to seeing him have.