Knicks coach Mike D'Antoni is an eternal optimist — almost to a fault, he acknowledges. Despite being down, two games to none, to the Celtics in the opening round of the Eastern Conference playoffs, D'Antoni says his team isn't panicking. They're actually entering tonight's game as confident as can be, even though they may be down two stars. "We're disappointed, but we're confident we can still get the job done,'' said D'Antoni. "We're definitely not having our heads down or whatever.'' D'Antoni is confident, even though the availability of Amar'e Stoudemire (back spasms) and Chauncey Billups (strained knee) is in question. "We think we can get the job done, no matter what,'' said the coach. "It'd be great if those guys can participate, but if not, we have to win anyway.'' The Knicks have lost two tight contests in what has turned out to be a very exciting series. Besides the injuries, late-game execution has been New York's downfall. And while Celtics coach Doc Rivers acknowledges that his team has yet to put together a solid four-quarter game, D'Antoni said neither has his team, and that Boston's struggles are due in part to some rare defensive intensity by the Knicks.