WALTHAM, Mass. — The usual beds. The usual lockers. The usual baskets.

The usual questions.

The Celtics are back in Boston for Game 5 of their Eastern Conference semifinal against the Cleveland Cavaliers, back where they're unbeaten so far in the playoffs after a regular season in which they posted an NBA-best 35-6 home record.

But it's their 0-5 road record that has them worrying.

"There is some frustration," center P.J. Brown said Tuesday after the team's walkthrough and film session. "But up to this point, it hasn't gotten under our skin."

Despite going 31-10 away from Boston in the regular season — also an NBA best — the Celtics have yet to win on the road in the playoffs. The slump allowed the lowly Atlanta Hawks to force them to a seventh game in the first round, and it could be their doom against the more formidable Cavaliers and star LeBron James.

"The key is winning the series. Whether it's at home or on the road, you just try to win it," Pierce said. "It's a three-game series, with two of them at home."

Asked if there was a danger that his players were using their home-court advantage as a crutch, Celtics coach Doc Rivers said, "The danger is that you're playing on the road right now against really good teams.

"We earned that right to have home-court advantage," he said. "I don't think it has anything to do with why we haven't won a road game. We haven't played well on the road, and we have to do better."

Thanks to their 66-16 regular-season record, the Celtics could theoretically win their 17th NBA title without ever winning a road game.

No team's ever done that, though, and the Celtics don't really want to be the first.

"I'm not even thinking about a Game 7. That's definitely the idea: Get a win (Wednesday) night and try to close it out in Game 6," Pierce said. "We definitely have to play well (in Game 5), because we haven't been playing well on the road.

"You kind of want to treat it like a Game 7, because you can't count on winning Game 6."

The Cavaliers are in a similar spot in the series — 2-0 at home and 0-2 on the road — but they can't fall back on having the deciding game at home. On the other hand, Cleveland won an away game in the first round, closing out the Wizards 105-88 in Washington in Game 6.

"It just shows how strong you are as a team to be able to go into a hostile environment and stick together and come out with a win," Cavaliers guard Daniel Gibson said, adding that coming to Boston a second time will help.

"Once you've experienced an environment, going back to it is kind of like, 'We've been here before.' And we felt like we were right there to win a game. So we know what we're capable of doing on their floor and we're going into it with a lot of confidence."

The Cavaliers are hanging onto their memories of a Game 1 loss in Boston that wasn't decided until James missed a layup with 8.5 seconds left. The Celtics won Game 2 more handily, but they have yet to come close in Cleveland.

"You can win all your home games and get a championship that way. I don't think that has ever been done," Cavaliers coach Mike Brown said. "You've got to get some road wins to be a champion; at least that's the history of the game.

"I tell our guys, if you expect to win in the playoffs, you've got to know how to defend and you've got to know how to win on the road.'