Updated

By Mark Lamport-Stokes

LOS ANGELES (Reuters) - With coach Doc Rivers pulling the strings like a puppet master, the Boston Celtics defied their critics and shrugged off a late season slump to reach the NBA Finals for a 21st time.

Rivers maintained his trust in a team that limped 27-27 over their final 54 regular-season games, preferring to rest some of his top but aging players to keep them fresh for the playoffs.

As with so many moves made by the astute Rivers, what may have initially appeared risky and even foolhardy turned out to be yet another master stroke in the bigger picture.

The invigorated Celtics eliminated LeBron James and the top-seeded Cleveland Cavaliers in the second round of the playoffs before beating the Orlando Magic in the Eastern Conference championship series 4-2.

"This is where we thought we would be," Rivers told reporters after the Celtics had beaten the Magic 96-84 in Game Six at an electric TD Garden in Boston. "This is what we talked about before the season started.

"We did go through tough times. We started out so well and I thought after 28 games you could say we felt like we were the best team in the NBA. After that we had injuries, we fell apart and we struggled finding ourselves."

Two members of Boston's pivotal 'Big Three' -- Kevin Garnett and Paul Pierce -- were sidelined during the regular season.

Garnett was out for almost a month while recovering from a hyper-extended right knee while Pierce missed five games in December because of a knee infection and three in February with a strained thumb.

GAME PLAN

"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.

"The one thing I did learn through the injuries was we were not good enough injured. There were no guarantees but we had a chance healthy. So my gamble was let's take health. So we lost some games, but we got healthy."

Rivers shrugs off suggestions that Boston's big three of Garnett, Pierce and Ray Allen are not the force they were when the Celtics steamrolled the Lakers 131-92 in Game Six to clinch the 2008 NBA championship.

"This starting five has never lost a series, ever," he said. "As a coach, I just believed that I saw what they did and what they had. We kept saying as a staff, it's in us. We've got to try to get it back out of us."

Garnett (aged 34), Pierce (32) and Allen (34), plus Rajon Rondo and Kendrick Perkins, have won seven playoff series as a unit and their collective physical presence could be a telling factor in the best-of-seven NBA Final against the Lakers.

"We have a team where the core players here have won a championship," said Pierce, the 2008 MVP of the championship series. "Once you get that under your belt, that's experience you can't take away.

"When the playoffs start, we know we have that kind of experience and we know how to win games because of the team that's been together over the last few years. We have the same starting five that won a championship."

The Celtics, a storied franchise made great by coach Red Auerbach and players such as Bill Russell and Larry Bird, have so far enjoyed a significant winning edge against the Lakers when it matters most.

Eleven times the teams have met in the showpiece NBA Finals with Boston triumphing on nine occasions.

(Editing by Ian Ransom)