BOSTON — 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 tonight 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.

"I'm a little shocked that he's 8-for-42, but this is what we work on. We work on trying to contain him," said Pierce, who was 2-for-14 in Game 1. "LeBron is what makes them go. And if we can somehow control him, we control their team. And with the help of the guys around me, we've been able to do that."

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.

"Being down 0-2, that's a tough hole to dig yourself out of. But if we want to win the series we've got to do it," James said, noting the Cavaliers lost the first two games to Detroit in last year's playoffs but won four straight to reach the NBA finals.

"We've been in this situation before," said James, who offered encouragement along the bench as the final seconds ticked off. "I've got to let them know that I'm not frustrated."

The message was NOT received.

"He's got to be frustrated," Cavaliers guard Wally Szczerbiak said. "He's such a good player. He puts so much on his shoulders."

James will have a more welcoming crowd for the next two games than the Boston fans who serenaded him with a chant of "Over-rated!" as he went 1-for-11 over the second and third quarters.

This time, the poor shooting 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. 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, and 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.

Wallace, who attributed the problem to allergies, sat on the bench for the second quarter and took some shots during halftime warmups, but did not return to the game.

"As bad as my head was hurting me, it's always hard to be out there and see your teammates struggling," he said.

Wallace will be re-evaluated when the team returns to Cleveland, Cavaliers spokesman Tad Carper said.

Pierce and Allen (0-for-4 in Game 1) 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 scored 11 points in the third quarter, including the first four of the second half as the Celtics scored 10 straight 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.

"It was good to see Ray get it going. I thought that lifted everybody up on our team," said Celtics coach Doc Rivers, who called the first several plays of the second half for Allen. "I made a concerted effort. I told the coaches at halftime, 'We're going to him over and over again. We've got to get him going."'

Allen joked that he had forgotten what it felt like to make a basket.

"I think everybody was relieved," said the 33-year-old All-Star, who like Garnett arrived in an offseason overhaul that helped the Celtics post the biggest single-season turnaround in league history. "It was as if I was just traded here all over again."

Cleveland took an early eight-point lead, but the Celtics erased it with Garnett and Pierce on the bench. 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.

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. ... Pierce spent some time on the bench after having the thumbnail on his right hand nearly torn off early in the second quarter. He returned with a bandage. ... Boston's Kendrick Perkins came out with three minutes left in the first quarter with a bloody nose. He sat out the rest of the quarter trying to stop the bleeding with a towel then returned in the second quarter.