The Celtics' Ray Allen, Kevin Garnett, and Paul Pierce have been having postgame powwows to go over wins and losses since joining forces last season. Considering that the defending NBA champions (28-5) departed for a four-game West Coast trip with the best start in league history, those post-buzzer talks had been mostly short and lighthearted.

But after a 91-86 loss to the Trail Blazers Tuesday, the Celtics' third loss in four games, they had a more lengthy discussion.

"That's kind of like the meetings of the minds," Allen said. "When you're frustrated, you have to just find a way to make sure we talk it out. We just try to understand by bouncing [things] off of each other. What are we doing? What's going on? How did we talk?

"Every game we go in there and sit back and say, `What do you guys see? What's going on?' That's it."

So what did the three talk about after the Portland loss? "Is that something I want to share with ya'll?" Garnett quipped.

Hey, the media had to ask. But even without the details, it's not hard to figure out the wide range of topics Allen, Garnett, and Pierce had to chew on.

During the trip, Boston lost two straight for the first time this season, against the Lakers and a lowly Golden State squad without two starters. Portland was also without leading scorer Brandon Roy.

Garnett's floor time has been a concern of late. Fatigue seems to have set in with the Celtics, who have already played 33 games. Boston's bench play is more miss than hit right now, too.

With Dikembe Mutombo back in Houston and Boston's Patrick O'Bryant not ready to play significant minutes, the Celtics couldn't counter the length that bothered them in the losses to the Lakers and Trail Blazers.

Scoring down the stretch has been a problem, too, as Boston scored a season-low 16 fourth-quarter points against the Lakers and were outscored, 35-17, in the fourth quarter by Golden State and, 27-22, by Portland.

"We are a different team from last year," Pierce said. "We have different players coming off the bench with a little bit different roles. It's just about us being definitive in our roles and understanding what we are first, a defensive team. We have to play offense, too. Get back to that."

Because of a combination of needed rest, lack of time, and travel, the Celtics haven't practiced since Dec. 20 and are in desperate need of some fine-tuning. Foes are also finding cracks in Boston's mighty defense. Frustration mounted for Celtics assistant coach Tom Thibodeau, in charge of team defense, as he was slapped with a costly technical during the Portland game.

"Teams are going to make adjustments to how we are playing," Garnett said. "Our style of defense, teams aren't necessarily figuring it out but they are making adjustments to that."

Oh, yeah, there certainly was discussion among "The Big Three" about the confused referees who called a technical but still allowed a Portland basket to count late in the second quarter despite six Trail Blazers being on the floor.

"It's one of the worst games of officiating I've seen in a while," Garnett said.

Said Pierce, "I've never seen anything like it. I still don't understand why they counted the bucket."

When things are good, "The Big Three" have quick postgame talks. But on the rare occasion when things are bad, like Tuesday, Allen, Garnett, and Pierce are the last three players to leave the locker room.

"When you win, you don't even have to talk about the game," Allen said. "You just go in the back and you relax. You're chillin' after spending a hard day's work and having a little something to eat. But when you lose, that's what we do, we sit back and talk it out.

"Any time we've lost it's the same because we take losing hard. When we talk about what went wrong, we can talk about the same thing every conversation. Any team that loses, loses the same way. Teams win the same way every time. It's the same stuff.

"Whatever weaknesses we have we kind of put that as far back in the locker room as we can and just take care of the good stuff."

One thing "The Big Three" have determined is that with the NBA's best record, it would be foolish to panic.

"We're good. It's unfortunate, though," Garnett said. "We are not a perfect team. We are a team that is a work in progress and we are going to continue to be that. We have a lot of room to improve and it shows. It's not the end of the world. But we'll reevaluate and get back home, get back in the gym, and get back to work like we usually do."

Said Allen, "I don't put much on [the losing]. Experience tells you that you're not as good as you think you are. You're not that far from being bad. But when you're bad, you're not that far from being good. You just have to find a way to improve on the things you've been doing. We can't get down on ourselves."

After a lengthy meeting of the minds after the Portland loss, maybe the cure for the Celtics' recent woes was discovered.

"We just always have to have each other's back," Allen said. "We talk it out. We care about winning. That's how we like to look at it. We like to talk it out."

Said Garnett, "We are a good team.

"We're going to go back to the drawing board and see what we can do."

Marc J. Spears can be reached at mspears@globe.com