Boston, MA (AP)  -- Paul Pierce and Ray Allen found their shooting touch. LeBron James can only hope he left his in Cleveland.

Pierce scored 19 points, Kevin Garnett added 13 with 12 rebounds, and Allen broke out of a seven-quarter scoring drought with 16 points to help the Boston Celtics beat the Cavaliers 89-73 on Thursday night and take a 2-0 lead in the Eastern Conference semifinals.

One game after going 2-for-18 from the field and missing his last six shots, including a layup to tie the game with 8.5 seconds left, James missed his first three tries and finished with 21 points on 6-for-24 shooting.

This time it was contagious: The Cavaliers shot 35.6 percent in the game, hitting just 11.8 percent in the second quarter as Boston turned an eight-point deficit into a nine-point lead.

Game 3 is Saturday night in Cleveland. The Cavaliers will need their crowd to pull them out of their funk because the Celtics are 6-0 in the playoffs in Boston, and they would have the homecourt advantage through the NBA finals.

James -- who was serenaded by the fans with a chant of "Over-rated!" -- could benefit most of all. He went 3-for-8 from the field in the first quarter but went 1-for-11 over the second and third when Boston took control.

From early in the second quarter to early in the third, a span of 13:41, Boston outscored Cleveland 36-10.

Zydrunas Ilgauskas had 19 points for the Cavaliers.

Cleveland reserve Anderson Varejao had 10 rebounds in 32 minutes after forward Ben Wallace went to the locker room just 3:40 into the game due to dizziness. He sat on the bench for the second quarter and took some shots during halftime warmups, but did not return to the game.

Pierce (2-for-14 in Game 1) and Allen (0-for-4) snapped out of whatever ailed them. Pierce did it right away, with seven points in the first quarter, but Allen took a little more time.

The third member of Boston's Big Three hadn't scored since hitting a 3-pointer with 8:48 left in the third quarter of Game 7 against Atlanta. Boston finished off the Hawks with just seven points from the Allen, who shot 3-for-12 in the first-round finale.

He missed his first four shots Thursday, but got the ball back for the first basket of the second half as the Celtics scored the first 10 points of the third quarter to take a 54-36 lead. The Cavaliers cut it to 12 on James' only basket of the quarter, but they spent most of the fourth quarter trailing by 20.

The Celtics erased an eight-point deficit with Garnett and Pierce on the bench, and the Boston subs outscored Cleveland's 26-4 in the first half. In fact, the Celtics bench outscored the Celtics starters 26-18 in the half.

The Cavaliers led 21-11 in the first quarter, and they still led by seven in the second before their shooting went cold. The Celtics took their first lead of the game at 28-27 when James Posey stole a bad pass from Delonte West and went in alone for the dunk, then Sam Cassell hit a 3-pointer to complete the 10-0 run.

But Boston wasn't done.

Wally Szczerbiak tied it with a 3, then Garnett fed Leon Powe with a behind-the-back pass to start a three-point play. Allen's steal and feed set up Garnett on a breakaway dunk; West reached from behind to try to foul but only wound up giving Boston another three-point play.

Notes:@ The Cavaliers switched from the burgundy uniforms they wore in Game 1 to primarily blue ones Thursday. ... Celtics basketball boss Danny Ainge said the NBA has reversed a flagrant foul call against Cassell from Game 1. ... The Celtics went 7-for-16 from the line in first half. ... Sasha Pavlovic was the highest-scoring Cleveland sub, with five points.