Boston’s Leon Powe, left, and Houston’s Brent Barry, right, get tangled up during the second half on Tuesday in Houston. Associated Press Photo.

HOUSTON — Celtics coach Doc Rivers chatted with Rockets general manager Daryl Morey after Boston’s 103-99 victory over Houston on Tuesday night.

“Y’all are going to be great,” Rivers said. “I’m telling you.”

Maybe so. But the defending NBA champions showed the Rockets how far they still have to go.

Ray Allen scored 29 points, Kevin Garnett added 14 points and 11 rebounds and the Celtics shut down Ron Artest and Yao Ming to hand Houston its first loss of the season.

Tracy McGrady scored 26 points, but couldn’t rally the Rockets down the stretch.

The Celtics arrived in Houston thinking more about their 95-79 loss to Indiana on Saturday than the buzz they’ve heard about the Rockets.

“With Artest coming here, I know they see what we did the previous summer in having three guys who really can play and really can score,” said Allen, who hit 11 of 15 shots. “You have a tendency to get caught in the hype of the wrong team and you start to believe it. What we did, we came out here, we lost the last game, and we needed to come out here and do the things we do that make us successful.”

The Celtics led 101-97 when McGrady rose for a 3-pointer and was fouled by Tony Allen. McGrady landed awkwardly and grabbed his sore left knee as Rivers protested the call, claiming McGrady was trying to pass. He was given three foul shots and made two, cutting Boston’s lead to 101-99.

Eddie House hit two free throws at the other end with 9.6 seconds remaining. Brent Barry then shot an airball and Garnett caught it to secure the win.

“We did not play well at all,” said Artest, who missed 13 of 16 shots and scored 15 points by sinking six free throws. “Usually you can say you’ve got to give them credit. But there were things that we could’ve done better to pull out the victory.”

Paul Pierce added 13 points and nine rebounds for the Celtics. Yao went 4-for-14 from the field and scored eight points for Houston.

“Probably one of my worst games of all time,” Yao said.

Houston’s reserves helped keep the Rockets in the game. They trailed 81-78 after three quarters.

Yao, Artest and McGrady went a combined 0-for-8 to start the fourth quarter and the Celtics led 93-86 with 31⁄2 minutes left. McGrady converted a three-point play, but Ray Allen hit a 3-pointer at the other end. McGrady then hit a shorter shot and Ray Allen answered again.

Luis Scola scored twice to cut Boston’s lead to 98-95. Out of a timeout, Garnett swished a shot from the wing with 59.6 seconds left and McGrady missed a long jumper on Houston’s next trip down.

The Celtics ended the Rockets’ 22-game winning streak last season with a 94-74 win at the Toyota Center on March 18. Yao missed that game with a stress fracture in his left foot.

Houston feels more equipped to win games like this with defensive specialist Artest. He guarded Pierce from the opening tip and stole the ball on Boston’s second possession. Yao, guarded by 6-foot-10 Kendrick Perkins, had a dunk and two hook shots in the first five minutes as Houston took the early lead.

But Yao went to the bench with his second foul with 6:35 left in the quarter and the Celtics went on a 15-4 run, hitting seven of nine shots. Pierce scored only four points in the first quarter, but Rajon Rondo had 10 and Boston led 28-22.

Yao returned with 10:52 left in the first half. With Yao backing off, Glen Davis grabbed an offensive rebound and scored, part of a 15-5 Celtics run. Davis converted a three-point play, drawing Yao’s third foul, to put Boston up 43-27 with 7:56 remaining in the half.

Yao went out again and the smaller Rockets’ lineup mounted a 25-4 run, sinking nine straight shots, including three 3-pointers. The Celtics hit only one field goal and committed three turnovers in the five-minute stretch, and Aaron Brooks’ jumper put Houston ahead 52-47.

Houston’s bench contributed 25 points.

“We were in pretty good shape with Yao hardly playing in the first half,” said Rockets coach Rick Adelman.

Ray Allen stopped Houston’s run with a three-point play and swished a 3-pointer on the next possession to put the Celtics back in front. Pierce hit a 3-pointer in the final minute and Boston led 58-53 at the break.

The Celtics hit 11 of 16 shots in the third quarter to keep their lead heading into the fourth.

Suns 114, Nets 86

EAST RUTHERFORD, N.J. — Raja Bell hit all six of his 3-pointers and scored 22 points, and the Phoenix Suns shot 63 percent from the field in beating the New Jersey Nets 114-86 on Tuesday night.

Steve Nash added 12 points and 11 assists, Shaquille O’Neal had 18 points and six rebounds and Amare Stoudemire added 14 points as the Suns won for the third time in four games.

Vince Carter had 19 points and Yi Jianlian added 15 and eight rebounds for the Nets, who lost their second straight game.

For the game, the Suns were 43-of-68 from the field, and 12-of-18 from 3-point range. The Nets shot 34 percent, hitting 28 of 83 shots.

Mavericks 98, Spurs 81

SAN ANTONIO — Dirk Nowitzki scored 30 points, Jason Terry added 29 in his first start of the season and Dallas sent the Spurs to their first 0-3 record in 35 years.

Dallas (2-2) also got 14 points from Josh Howard. The Mavericks shot 53 from the floor compared to 42 for San Antonio. Dallas outrebounded San Antonio 48-38.

The Spurs (0-3) are off to their worst start since opening the 1973-74 ABA season 0-4. It was their first season in San Antonio after playing in Dallas as the Chaparrals. The Spurs joined the NBA in 1976.

Tony Parker led San Antonio with 22 points and Tim Duncan scored 19 as the Spurs continue to play without Manu Ginobili. He’s not expected back until December after surgery to repair his left ankle.