WALTHAM, Mass. –– Losing all five of their road playoff games has not put the Celtics in a state of panic.

“I admit there is some frustration. There is a level of that,” veteran forward P.J. Brown said, “but up to this point is hasn’t got up under our skin. It hasn’t got out of hand. Guys are very confident that we’re going to do what we have to do at home … and we look forward to going back to Cleveland for Game Six Friday night.”

The Celtics should be frustrated. They had the best regular-season record in the NBA, 66-16, and the best road record, 31-10, but looked like a different team while losing three to the young Hawks in Atlanta in the first round and two to the revitalized Cavaliers in Cleveland in this round.

They’re home tonight for the crucial Game Five at TD Banknorth Garden, and the home-court advantage never looked better. Only six visiting teams have prevailed on the parquet since the start of the season last October, and as long as that number remains the same, the Celtics have the upper hand.

“We’ll have a good crowd, and the atmosphere will be really, really good. We’ll take advantage of that, but as a team I’d like to see us be consistent and play a level of basketball where we’re playing good at both ends of the floor for 48 minutes. That’s something I haven’t seen as much as I’d like to,” Brown said.

The Celtics spent about 90 minutes yesterday reviewing their 88-77 loss in Monday night’s Game Four that tied the series and going over Xs and Os. At this point there’s little else to do, except hope that Paul Pierce and Ray Allen, scoring less than their season averages, will snap out of their slumps; that Sam Cassell, 0-for-11 off the bench in Cleveland, will find his shooting touch; and that Kevin Garnett, scoreless in the fourth quarter of Game Four, will hit a big shot near the end of a close game again.

Coach Doc Rivers is not alarmed by his team’s road woes. He is more impressed with the Cavs.

“The danger is the team you’re playing on the road right now, they’re really good,” he said. “Basically you just got to feel you’re going to break through, but you do have home court. I don’t think we use it as a crutch. We know it’s there, and it’s not bad to have. We earned that right to believe, ‘You know what? We get to go back home.’ Having said that, I don’t think that has anything to do with why we haven’t won road games. We haven’t played well on the road.”

No, they have not. They shot 38 percent in Game Four and faltered in the fourth quarter. They got off to a horrible start in Game Three and shot 40 percent in the 108-84 blowout that was over in the first quarter.

But Cleveland was just as bad in the first two games in Boston, shooting 30 percent in Game One and 35 percent in Game Two. LeBron James shot only 8-for-42 from the field.

Most important, as far as Rivers is concerned, the Celtics still have a chance to win a road game.

“That’s all you want. You want to keep having that opportunity. If we still have this opportunity in the Finals and haven’t won one, we still have the opportunity. You just want to keep the opportunity of having a chance to win a road game going. That’s the key,” he said.

In other words, the point is winning the series, not one road game.

“We want to keep moving forward,” Rivers said. “They key is to win the series, and obviously it would be easier if we could do that by winning a road game. Having said that, we played all year to get home court.”

And tonight they will play to protect it.

“We all know what’s at stake. We know we need to win this game. … That’s what it’s all about right now,” Brown said. Tonight

vs. Cavaliers

8 p.m.

mszostak@projo.com