The Celtics only watched the first quarter of their loss to the Grizzlies, but that 12 minutes of film was all they needed to get the message.

“You could say that was enough,” Rajon Rondo said prior to Friday’s game against the Pacers. “We knew what happened in the game. We didn’t need to watch the whole game.”

Just two days after losing by 20 points to the Grizzlies, the Celtics bounced back with a 122-103 blowout win over the Pacers. (Recap.) In spite of seven lead changes early in the game, Boston never trailed after there was 2:42 left in the first quarter. This time, Doc Rivers said, the Celtics did not get discouraged by early disappointment.

“They were stung the other night, but also I warned them going into tonight – just because you want to fix it, if things don’t start out right, you can’t hang your head or panic about it,” he said. “And it actually did start out in some ways like the other night. We got three or four great shots to start the game, none went down. The difference was we hung in there and we got some stops, and then we got on a run.”

The Celtics led by as many as 25 and tied their season mark for most points in a quarter with 38 in the second.

Not only did the starters play well (Paul Pierce led the team with 20 points), but the bench added 54. It was the second unit’s largest contribution since November 3, when it scored 62 points against the 76ers.

The Celtics seemed to have learned from their loss to the Grizzlies, and here are three things we learned from their win over the Pacers:

AN AGGRESSIVE ROBINSON CAN SPARK THE CELTICS

The play brought the Garden crowd to its feet.

With 45 seconds left in the first quarter, Nate Robinson picked off a pass at half court and nailed a 3-pointer. The shot put the Celtics up, 29-23, their largest lead of the quarter and one that they never surrendered.

“It just felt like the right thing to do at the time,“ Robinson explained. “You get a steal and they can’t load back up on defense. That’s like a 70 percent shot whenever somebody gets a steal and just casts it up and you’re liable to make it. I shoot with a lot of confidence. I feel like I can make every shot when I shoot the ball, and I just let it go.”

Robinson practically made every shot he took. He knocked down his first five 3-point attempts and finished the night with 15 points (5-9 FG, 5-6 3PG). He scored 12 points in a span of just seven minutes to pass his combined total from the prior four games.

Rivers noted that Robinson has a tendency to pull back at times on the court. Fortunately for the Celtics, that wasn’t the case on Friday.

“Every night is different,” Robinson said. “You’ve just got to take the good with the bad, I guess, and tonight we were on. I hit the open ones they gave me and hopefully I can continue to make them throughout the rest of the season.”

Kendrick Perkins was honest before the game. He knew his rebounding productivity had gone down and was not denying that he wants to improve it.

“I think on the offensive end, when I’m attacking the offensive glass sometimes I feel like I’m getting boxed out by two people. But on the defensive end, I feel like I’ve got to do a better job of rebounding, especially these last few games,” he admitted. “Like I said, it happens to everybody. I figure at some point in the season you go through a time that you’re struggling, no matter what it is. I’m not perfect, but I’m trying to get it done.”

Perkins’ effort did not go unnoticed against the Pacers. He led the team with seven rebounds, but Rivers was pleased with another aspect of his game.

“Perk doesn’t get a lot of credit tonight,” he said. “I thought this was one of his best games in a long time because of the picks. I mean, he was a human-pick machine tonight, just flying around, got guys open, and they got the points and Perk got a pick. You don’t get an assist for a pick, but if you did, he probably would’ve led the team in assists tonight.”

Setting picks and getting his teammates open is exactly the kind of contribution Perkins can be pleased with. Even if he has been struggling on the glass, he isn’t going to consume himself with that stat line as long as he is doing other things to help the Celtics win.

“Sometimes rebounds fall your way, sometimes they don’t. I may go through a stretch where I get 13 rebounds a game, who knows?” he said. “But I don’t really go out there playing for stats. At the end of the day I go out there and try to get the win. However it takes for us to win -- if I go out there and I have two rebounds but I have six blocks, I’m pretty happy.”

FINLEY HAS FOUND NEW LIFE

Last month, Michael Finley scored a total of five points in seven games for the Spurs.

Now as a member of the Celtics, he has scored 24 in just three.

“He hadn’t made a shot in a month with San Antonio and now – I mean, you see it. Every time it leaves his hands, you’re shocked when it doesn’t go in,” said Rivers. “It’s a beautiful shot.”

Not only is Finley scoring, he is doing it efficiently:

• Five points (2-3 FG, 1-1 3PG) in eight minutes against the Bucks
• 10 points (4-6 FG, 2-3 3PG) in 14 minutes against the Grizzlies
• Nine points (4-5 FG, 0-0 3PG) in 18 minutes against the Pacers

Rivers suggested a change of scenery has helped Finley. The veteran agreed, citing the familiarity he had with many of the Celtics and the welcome by the organization. The team has made Finley feel right at home, and now he is working on feeling at home in its system.

“The offensive playbook is real complex, but they’ve done a good job of narrowing it down for me when I’m on the court, myself and Nate Robinson as well,” he said. “But I’m trying to learn as much as I can as quick as I can because I don’t want the team to slow down when I’m in the game. I think the coaches have a little confidence in me that I’m going to have to learn on the go, so to speak, and that’s the way we’ve been doing it.”