BOSTON — The Boston Celtics watched the misery unfold again, a poor performance that was tough to take the first time.

As video played of Tuesday night’s 91-84 loss to the Los Angeles Lakers, Tony Allen noticed Paul Pierce wasn’t enjoying himself.

“He seemed pretty upset in the film session,” Allen said Wednesday. “I just saw his gestures. It kind of looked like he felt he could do more.”

Pierce has plenty of room for improvement in Game 4 of the NBA finals tonight. He made just four shots before tossing in a meaningless layup with 5.1 seconds left, and finished with 15 points, two rebounds and two assists. In Game 2, the Celtics won 103-94 in spite of him; he missed 9 of 11 shots and scored just 10 points after leading the team in the regular season with an 18.3 average.

The MVP of the 2008 finals ran into foul trouble Tuesday, reducing his aggressiveness. Rarely did he drive, which usually gets him a layup or two free throws. At the video session, Pierce told Coach Doc Rivers why.

“It’s funny,” Rivers said. “I said, ‘Paul, that’s a driving lane. You’ve got to get to the basket.’ His response was, ‘I was worried about getting another foul.’ It’s tough to play that way.”

The futility spotlight focused on Ray Allen, who missed all 13 of his shots and finished with two points Tuesday. But he and Pierce got off to equally poor starts, both missing all five of their shots in the first quarter.

“They had an outstretched arm in front of my ball all night,” Ray Allen said. “I just move forward and just focus on getting good rest and being ready.”

For Pierce, being ready means avoiding foul trouble. On Tuesday, he went to the bench with two fouls with 2:10 left in the first quarter. After picking up a fifth foul with 11:21 to go in the game, he spent 3:06 on the bench.

“When I go out there and I’m in foul trouble, it’s difficult, which was the case in Game 3,” Pierce said. “I can do more if (the Celtics) need me to do more. Obviously I’m going to probably have to do more.”

He also struggled in Game 3 in the 2008 finals against the Lakers. He missed 12 of 14 shots, managed just six points and was saddled with five fouls. But in the next game he led the Celtics with 20 points in a 97-91 win that gave them a 3-1 series lead. They won their 17th championship in six games.

“He did have a great finals, and I thought in that whole (playoff) run he had a great momentum,” Kevin Garnett said.

Now Pierce has another chance to bounce back from a bad Game 3.

“We need Paul to be Paul Pierce, ‘The Truth,’ ” Garnett said. “But it has to be something that is a flow and within everybody’s flow of the game.”

Pierce agrees. As long as he’s helping the team in other ways, poor shooting doesn’t bother him as much. His defense has been solid against Ron Artest, who went 1 of 10 in Game 2 and 1 of 4 in Game 3.

The Lakers also have played outstanding defense against Pierce and Allen.

“It’s a little different with Ray,” Lakers forward Luke Walton said. “He sets a deadly catch- and-shoot. He gets (the ball) off so quick that it’s more not giving him any space, be on him as soon as he catches, crowd him, make him put it on the ground.

“Paul is a great penetrator, great at getting to the line, so you don’t want to force him into a drive.”

Pierce sank 369 free throws, the 14th most in the regular season. Kobe Bryant, ranked 11th with 439, is the only player in the finals with more.

“Obviously I probably can do a little more to help this ballclub,” Pierce said, “but it’s going to be a team thing. It’s not about one individual.”

That was painfully evident when the Celtics sat through a long video session of Game 3.

“You look at the tape and you see the things that you’ve done wrong, what you could have done better,” Pierce said. “It’s very frustrating because all year long, all summer long before the season starts, you put so much into it for these moments right there.”

His next moments come tonight.

Lose and he and the Celtics must win three straight games to take the title. Win and they’re back on track in an even series with another home game Sunday night.

“Paul’s our captain and he’s going to adjust” to the way the referees call the game, Glen Davis said. “He’s capable of having huge games and he’s due for one. I expect Paul Pierce to be here and deliver.”