MIAMI -- LeBron James didn't appear tired, Dwyane Wade's knee looked just fine, and new addition Ray Allen came off the bench to give the Heat another potent threat.
And just as importantly, Chris Bosh, Miami's sometimes forgotten star, delivered a big finish.
On a night the Heat celebrated their 2011-2012 NBA title with a ring ceremony, their championship defense began with an impressive performance at American Airlines Arena. The Heat beat the Boston Celtics -- Allen's old team -- 120-107 Tuesday night.
The Celtics got as close as 111-107 with 2:05 remaining, but Bosh scored on a drive to the basket and then added three free throws and a dunk on Miami's next three trips to squelch Boston's threat. Bosh finished with 19 points and 10 rebounds.
James had a busy offseason with a run to Olympic gold and various promotional appearances all over the world. But he looked to be in stellar form Tuesday, putting up 26 points and 10 rebounds.
Wade, who had off-season surgery, finished with a game-high 29 points.
And Allen, who signed as a free agent after deciding to leave Boston, added 19 points. .
Paul Pierce led the Celtics with 23 points, and Rajon Rondo added 20.
The Heat led 31-25 after the first quarter and extended the advantage to 62-54 at halftime.
Miami, which focused on adding more shooters in the offseason, went 3 of 4 on three-pointers in the first quarter, including 2 of 2 by Shane Battier and 1 of 1 by Allen.
When Allen came off the bench and hit his corner three on his first attempt, the crowd erupted and later chanted: "We got Ray!"
For the half, the Heat made 5 of 9 three-pointers and was paced by James' 14 points and eight rebounds. Wade added 13 points, and Allen had 11.
The Celtics, led by 16 points in the half from Pierce, were just as sharp in the first half. They made 3 of 5 on three-pointers and shot 48.7 percent from the field overall. The Heat shot 50 percent.
Boston, though, was hampered by 10 first-half turnovers, five more than the Heat.
NOTES: Before the game, NBA Commissioner David Stern was on hand to help the Heat celebrate last season's league title. A championship banner was raised to the rafters, where it will keep company with the Heat's 2006 flag. ... Players, coaches and other personnel received their championship rings during the ceremony. ... There was one slip in the festivities: Stern, who was greeted by boos, referred to this week's storm that hit New York City as "Hurricane Katrina: instead of Sandy.