Some big-game hunting

Coach Doc Rivers stopped just short of calling the Celtics' contests against Golden State tonight and Utah Wednesday night ''must-win" games. But he knows the outcomes could set the tone for the rest of the season, especially with Boston heading west Christmas Day.

The Celtics have reached another critical juncture. The last came after an embarrassing loss in Atlanta. This one occurs after an equally embarrassing loss in Chicago.

The Celtics need to regroup -- and fast. But more than that, they need to find defensive consistency. Same old story. But they need to stop talking about it and figure out a way to duplicate the effort they displayed in the second quarter against the Pacers Dec. 14 in an 85-71 win. They need to stop congratulating themselves for a handful of defensive jobs well done and recognize one quarter is not a building block for better defense if eight poor quarters follow -- as they did against the Bucks and Bulls.

''We've got two games at home," said Rivers. ''We need them both. We really do. I would say this is the first time this year that we have two games that are close to must-wins. I don't ever think anything is a must-win unless you're in the playoffs and it's Game 7. But these two games are vital for us for this season."

Without a win or two, the Celtics could lose all confidence just as quickly as they lose defensive focus. The Celtics seem to reach a point during games when they lose interest defensively. It is not a question of ability. Never has been. It is a question of effort and focus.

As Paul Pierce tried to explain, the Celtics don't execute in games the way they do in practice. He could not come up with a reason. He just repeated his usual pablum about the Celtics staying together and remaining optimistic because they really aren't that far away from being a good defensive team.

''Being a veteran, I've been through times like this before," said Pierce Saturday. ''Losses like this really don't shake me. I've lost like [we did against Chicago, 118-86, Saturday] maybe two or three times before. We've always got tomorrow. Hopefully, guys will know that we have to put this behind us."

The last two games have produced some of the worst stretches of defense by Boston this season. Overall, Boston is allowing opponents to shoot 46 percent, 22d in the league.

''The coaches are doing a decent job of giving us a scheme and, for the most part, everybody is in tune to it," said Raef LaFrentz.

''Everybody knows what's going on, but knowing what's going on and executing are two different things. With this team, especially, everything feeds off our defense. We are an athletic group and, if we can get stops, we can get out in transition and get easy hoops.

''The telling tale can be seen in [opponents'] shooting percentages. Any time you look at a stat sheet, look at the shooting percentage and that will tell you a lot about what our defensive effort was."

The Celtics have not reached a point where Rivers believes they need to return to the drawing board.

''As a coach, you have a way you think the game should be played," said Rivers. ''You don't change that. We've just got to do it better. It starts with me and I've got to get the team going."

Dan Dickau underwent an MRI yesterday and was diagnosed with a ruptured right Achilles' tendon that likely will force him to miss the remainder of the season. He is scheduled to undergo surgery tomorrow morning with team physician Brian McKeon at New England Baptist Hospital. Dickau suffered the injury early in the fourth quarter against Chicago. He was averaging 3.3 points and 2.1 assists in 12 minutes a game as a third-string point guard. ''Obviously, we're very disappointed to hear the news about Dan," said executive director of basketball operations Danny Ainge. ''We were disappointed in that Dan had accepted his role with the team. He is a true professional and a good teammate." . . . Delonte West suffered a mild concussion in the second quarter Saturday night and is questionable for tonight's game, though the team is optimistic he will be available.