It is hard to believe that it was one year ago when the then-defending World Champion Boston Celtics lost their Christmas Day NBA Finals rematch with the Los Angeles Lakers.The NBA talking heads will tell you that not only did the Lakers snap the Celtics’ 19-game winning streak; they also robbed the Green of their championship mojo. The loss was one that the Celtics never fully recovered from, and it was a win that propelled the Lakers to a world championship.For the Celtics, Kevin Garnett, who had spent the majority of his career languishing in the obscurity of the Minnesota Timberwolves, the Christmas Day game marked a first for him.”It was my first Christmas game, and I was obviously blessed to be here,” Garnett said. “There’s a reason why teams are playing on this special day, so it had a playoff energy and a playoff atmosphere to it, absolutely. It’s tough when you lose against anybody. We probably took a step back.”Unlike last season’s Celtics team, which probably peaked in December rather than in April, this bunch of Celtics prides itself on restless dissatisfaction, says coach Doc Rivers.”You don’t have to play 48 minutes to win a game, but you have to play 48 minutes to win a playoff game,” Rivers said. “That’s the way we look at it. We’re getting better. Each game, I think we’ve improved as the year has gone on. That’s exactly what we want to do. We’ve had some lulls and we’ll probably have a couple of more. Who knows? But I like our mindset.”For the Celtics and their still-recovering superstar Garnett, they will get their chance to oust their ghosts of Christmas past this Dec. 25, and while their opponent will be different, the stakes will be the same. For it was this Christmas’s opponent, the Orlando Magic, who defeated the Celtics in last season’s playoffs and officially stripped the Green of their title of “Defending World Champions.”While it is arguably a foregone conclusion that these two teams will be playing for much bigger and better things later this spring, this Christmas the Celtics find themselves looking to reacquire that championship mojo they lost 365 days ago.