BOSTON — There were still 20 seconds left in the game when Paul Pierce decided he didn't need to see any more and headed to the locker room.

In the hallway, he repeated aloud: "One more. One more."

Pierce helped the Celtics open a 16-point, first-quarter lead, then watched as Rajon Rondo and Glen "Big Baby" Davis helped Boston coast to a 94-71 victory over the Orlando Magic and take a 3-0 lead in the best-of-seven Eastern Conference finals.

The most-decorated team in NBA history, the Celtics are one win away from their second trip to the finals in three years — and their 21st in all. No NBA team has ever lost a playoff series after winning the first three games.

"We're motivated for what's at stake. We see the big picture," said Pierce, who was the finals MVP when Boston won its record 17th NBA title in 2008. "We were coming home for two games on our home court. We're motivated. We can feel it. Guys know what its like to win a championship and play for a championship."

The Magic have to win Game 4 on Monday night to avoid a sweep and force the series back to Orlando. They'll need a better effort than in Game 3, when they fell behind early for the third straight game. This time, they didn't even mount a late charge to make it close.

"The most disappointing to me was that I didn't have our team better ready to play," said Magic coach Stan Van Gundy, who was himself knocked over late in the game when Kevin Garnett was pushed into the Orlando bench going after a loose ball. "It starts with me. It's my job. I'm the coach of this team. It starts with me and I'm not happy with where we had our team tonight or anything I did."

Pierce had 15 points and nine rebounds, Ray Allen scored 14 and Garnett added 10 points in just 24 minutes. But this time it wasn't the Celtics' aging all-stars that did the damage — it was the two youngest players on the roster, Davis and Rondo, who were born in 1986, the year that Larry Bird and the original Big Three won the last of their three NBA titles.

Davis scored 17 points, and Rondo added 11 points and 12 assists, and they also gave the team energy and defense that the Magic couldn't match, diving to the floor for loose balls and getting the crowd going with spectacular plays.

Davis celebrated one play underneath the basket with an ecstatic but odd session of running in place; the crowd went wild. Rondo outhustled Jason Williams down the court for a loose ball in the second quarter, diving to take it away and then getting up to beat him again for the layup.

"What he's doing is, he's leading the team," Celtics coach Doc Rivers said. "He's playing with great focus. He has a great sense of what to call offensively. And now he's giving an amazing effort, never giving up on any possession. When you have that speed and then you have that heart, you become a pretty good player."

One game after scoring 30 points, Dwight Howard had just seven and seven rebounds. Rashard Lewis was also disappointing, scoring four points on 2-for-8 shooting, missing all four 3-point attempts. Vince Carter and Jameer Nelson had 15 points apiece.

"This is a tough one to swallow," Carter said. "To come out with a sense of urgency — I don't feel like we really did that. They did a great job of really playing like they were down and they needed to win more than we did. And after about midway in that first, they started pulling away from us and we never recovered."

Ten times the Celtics have opened a 3-0 lead in a playoff series. Four times they've swept, and six times they won in five games.

But the Celtics only need to look down the hall for a reminder that they're not done yet: Just eight days ago in the same building, the Philadelphia Flyers completed their comeback after trailing the Boston Bruins 3-0 in the NHL's Eastern Conference semifinals.

Celtics fans either don't remember or don't care: They started chanting "Beat L.A!" at the start of the third quarter, when Boston led 75-47. The Lakers lead the Phoenix Suns 2-0 heading into Game 3 of the Western Conference finals on Sunday, and there's nothing the Celtics would like better than another go-'round with the archrivals they beat in '08.

"We've got to resist the temptation of looking forward. We've got to win a game," Rivers said. "They're going to come back in the next game, and they're going to give us their best shot. They're a competitive group, and we know that. Quite honestly, we're not good enough to let up. I can tell you that."

Pierce had eight points and five rebounds in the first quarter, when the Celtics scored the first seven points and then added a 14-0 run to open a 21-6 lead. Howard missed his first four shots, along with a pair of free throws, before he made one of two foul shots in the final seconds of the first quarter to cut the deficit to 27-12.

It was the third straight time in the series the Celtics opened a big lead, but in each of the first two games Orlando eliminated most of the deficit to get within a single basket in the final minutes.

This one only got worse.

"We can't hold our heads," Howard said. "This is a very tough situation, but if we already think about being defeated then we shouldn't even come for Game 4. We've got to just keep fighting and stay together."

In the second quarter, the Celtics scored seven straight points to extend the lead to 24. It was a 28-point game at the end of three, and Boston led by as many as 32 in the fourth before Rivers emptied his bench.

NOTES: Howard and Kendrick Perkins were called for double-technicals late in the first quarter. ... Carter made a second-quarter layup after a botched alley-oop that went off Perkins' head.