BOSTON (AP) -- The Celtics were supposed to be too old, too hurt, too inconsistent.
Boston coach Doc Rivers knew better.
The team that muddled through its last 54 regular-season games with a 27-27 record is headed to the NBA finals after winning Game 6 of the Eastern Conference finals over the Orlando Magic 96-84 Friday night.
" The first thing we said when we got in the locker room is this is where we thought we would be,'' Rivers said. " So don't be surprised. This is what we talked about before the season started."
An 86-77 win at Orlando on Christmas Day gave the Celtics a 23-5 record. Then injuries to Kevin Garnett and Paul Pierce took their toll and the Celtics were content to give them and others time to heal even if it meant risking losing games late in the season.
The strategy paid off and now Boston will play Los Angeles or Phoenix with a chance for its second championship in three years and 18th overall, an NBA record.
" That stretch the last month, we formed a game plan, and I thought it was the right plan,'' Rivers said. " Obviously, it didn't look right because we were losing games, but guys were resting and conditioning, and I thought that was the only chance we had."
That mediocrity didn't fool Magic coach Stan Van Gundy, not after the Celtics eliminated the Cleveland Cavaliers and LeBron James in six games. And certainly not after they won the first three games of the best-of-seven series against the Magic.
" They beat two very good teams, and made us both look like we weren't very good teams," Van Gundy said.
Boston's " Big Three" of Pierce, 32, Garnett, 34, and Ray Allen, 34, all made key contributions Friday.
Pierce led the Celtics with 31 points and 13 rebounds, Allen scored 20 and Garnett added 10 points and 5 rebounds. Throw in Nate Robinson's 13 points off the bench in the second quarter, and the Magic's chances of becoming the first NBA team to overcome a 3-0 deficit - there were 93 others - were slim.
" I never really think negative about losing, or being up 3-0 and something tragic happening,'' said Pierce, the MVP of the 2008 finals. " Even though one day it's possibly going to happen. ... I'm just glad we were able to prolong it one more year."
The Boston Bruins opened a 3-0 lead against Philadelphia this month in the NHL's Eastern Conference semifinals before the Flyers rallied to win in the same building. The Magic, who dressed in the same locker room where the Flyers celebrated their comeback, couldn't even force the series back to Orlando for a Game 7.
" To win four straight games, you've got to be perfect,'' Orlando forward Matt Barnes said, " and we weren't perfect tonight."
The Magic were far from it.
They led for just 11 seconds, trailed by at least 12 points throughout the second half and were outrebounded 56-44.
" Those guys played like they wanted to win the championship the whole series,'' said Dwight Howard, who had 28 points and 12 rebounds for the defending East champions. " That's why they're in the position they're in now."
Vince Carter scored 17 points, and point guard Jameer Nelson finished with 11 points and four assists but had five turnovers and was outplayed by Rajon Rondo, Boston's starting point guard, and Robinson, his backup.
Reporters and fans scoffed when Rivers said last month that Robinson, who struggled to get playing time since coming to Boston at the trade deadline on Feb. 18 and had never appeared in the postseason before this season, is " going to win us a playoff game."
He came off the bench at the start of the second quarter, when Boston led 30-19, and hit 3-pointers 90 seconds apart to help stretch the lead to 15 points.
" Nate Robinson was huge in the first half,'' Van Gundy said. " That was a huge, huge lift for them."
Orlando cut the lead to 55-42 at halftime, but the Celtics scored 11 of the first 13 points in the third quarter - including back-to-back 3-pointers from Allen 38 seconds apart.
" The one thing that Doc said all year was, `I like this team. I like the guys on this team. We can win it with the guys that are on this team," ' Allen said.
Last year, the Magic eliminated the Celtics in a seven-game Eastern Conference semifinal series that Garnett missed with a knee injury. The previous year, the Celtics won their 17th title in a six-game series with the Lakers.
" This starting five has never lost a series, ever,'' Rivers said. " We believed that coming into the season, and we just kept believing."
The finals will begin Thursday in Los Angeles or Phoenix. The Lakers lead the Western Conference finals 3-2, and a victory over the Suns in Game 6 on Saturday would set up the cross-coast rivals for a rematch of the 2008 finals - and 10 other championship series from 1959-87.
" We never take these moments for granted, especially at this point in my career where it's winding down,'' Pierce said. " I can see the light at the end of the tunnel. To get back here is a great accomplishment, but even greater if we win another one. "
NOTES: Rondo hit the court hard and was slow to get up after he was fouled by Jason Williams late in the final minute of the first quarter. He stayed in the game. ... The Celtics are 9-2 against the Los Angeles and Minneapolis Lakers in the finals. The Celtics and Suns have met once in the finals, when Boston won 4-2 in 1976. ... Celtics F Rasheed Wallace left the game in the fourth quarter with back spasms and did not return.