It was May 6, 1990, and the Knicks were protecting a scant lead in the fourth quarter of a decisive Game 5 at the old Boston Garden, when 33-year-old Larry Bird drove the baseline and went up for an uncontested reverse dunk.  “Him, of all people, trying to dunk — and missing,” Jeff Van Gundy, then a Knicks assistant, recalled of that Sunday afternoon.  With the invisible leprechaun in charge of making sure the ball splashed through the net taking a nap, the long rebound settled into the sure hands of another 33-year-old, this one in Knicks road blue. Maurice Cheeks quick-dribbled his way to the other end to nail a pull-up jumper.  Just like that, the building was drained of certitude and the Knicks pulled away to a victory that sent their grinning general manager — an old Celtics-hater named Al Bianchi — into the cramped corridor to puff on a victory cigar as Red Auerbach, the Celtics’ patriarch who would not live to see another Celtics title, walked by.  Twenty-one years later, we have a potential re-enactment at the point of attack with 34-year-old Chauncey Billups manning the position for the Knicks as they return to the playoffs for the first time since 2004 on Sunday night at TD Garden in Boston.  Like Cheeks, acquired for Rod Strickland in 1990, Billups joined the Knicks (with Carmelo Anthony) around the February trading deadline at the cost of a younger point guard (Raymond Felton).  Like Cheeks, he came with a championship ring to impress and inspire his wannabe teammates.  Like Cheeks, who had had many playoff battles in Boston during his prime with the 76ers, Billups has no great love for the Celtics, as a former conference rival with the Pistons and as a top 1997 draft pick dealt away by Rick Pitino’s Celtics after 51 games.  In effect, and in further indictment of Pitino, Billups was traded for Kenny Anderson.  “Everybody thought that I hated Rick and Rick hated me, and that wasn’t the case,” Billups said.  “Rick had signed for a lot of money. When I got traded, he just told me there was a lot of pressure on him to win and he wanted to get a veteran point guard.  “But it was tough to get traded at that point in my career. Third pick in the draft, you feel like you’re going to be there for 9, 10, 11 years.”  Instead, Billups became a journeyman, a perceived bust, wearing five uniforms in six years before evolving into an All-Star, Mr. Big Shot, in Detroit.  There are no hard feelings, no residual anger, he said, about his short-lived stay.  “My first couple of years, I did,” he said. “But none of the guys I played with, nobody’s really there anymore.”  Don’t believe Billups isn’t relishing this opportunity to participate in what promises to be an old-school, hard-knocks series because that is how these Celtics play and that is how his no-frills Pistons, champions in 2004, went about their business.  And for those who contend that the Knicks are playing with house money, in Stage 1 of their grand renaissance, Billups would argue on a more personal level that time is of the essence, just as it was for the point man 21 years ago.  In Game 5, 1990, Cheeks played all 48 minutes, had 21 points and 7 assists, his last great N.B.A. occasion.  After the Knicks beat the Celtics, breaking a 26-game losing streak at Boston Garden, they lost in the next round to the Pistons of Isiah Thomas and Joe Dumars.  Cheeks did return for the next season — one of turmoil and regression — but was gone by the time Pat Riley revitalized the franchise in the fall of 1991.  Who can say that Billups, like Cheeks, will not ultimately be a drive-by Knick, one of their few tradable assets next season, assuming the team picks up the option on what would become a $14.2 million expiring contract?  By next February, Billups could be part of the bait for Chris Paul or some other leveraged free-agent-to-be.  For now, his matchup with the crafty blur named Rajon Rondo is being called a key to this much-anticipated series.  “Although they got a lot of Hall of Famers, he is the kind of guy that makes them go,” Billups said.  But for all the talk about Billups’s chances of keeping Rondo in front of him, Coach Mike D’Antoni does have another defensive option, Toney Douglas.  Hence, the more important order for Billups will be on offense, not allowing the Knicks to make the Celtics’ lives easy by giving in to quick-jump-shot temptation. To win close games, the Knicks must execute in the fourth quarter against a premier help defense, space the floor, drive the ball, get to the free-throw line.  From Billups, they will need big shots, but also a calm, steady hand, an approach that doesn’t let his younger teammates succumb to the notion that time is their ally and the big February trade wasn’t really for now.  For Billups, there may be no playoff tomorrow in New York, and that is not the worst mentality to take into a series against the proud and favored former champions.  Because history does tell us that even the leprechauns are not a slam-dunk.
Chauncey Billups must do what Maurice Cheeks did for New York in its defeat of the aging Celtics 21 years ago.