Los Angeles - The Boston Celtics won the NBA Championship with a gritty defence, and they showed that down the stretch to knock the Houston Rockets from the unbeaten ranks.

Ray Allen scored 29 points, Kevin Garnett had 14 with 11 rebounds and the Celtics shut down the Rockets for a 103-99 road victory on Tuesday night, in an early season match-up of league powerhouses.

"I was really proud of our guys because it was a big game for them and for us," Celtics coach Doc Rivers said after his club improved their record to 3-1. "It was hard fought, physical game. Every time we got the lead they fought back."

Kendrick Perkins contributed 15 points with seven rebounds, while Paul Pierce finished with 13 points and nine boards for the Celtics, who rebounded from their first loss of the season against Indiana on Saturday night.

Tracy McGrady topped the Rockets (3-1) with 26 points and Argentine Luis Scola followed with 21 and nine boards.

"I had a pretty good game to keep us in the ballgame, but it wasn't enough," McGrady said.

However, Ron Artest struggled to score 15 points on an icy three- of-16 shooting, and Yao Ming finished with just eight points, hitting just four-of-14 attempts in 28 foul-plagued minutes.

It marked the first time the 2.29-metre (7-foot-6) Chinese All- Star centre failed to score in double digits since April 2007.

"The early fouls changed a little bit of my game, but cannot be my excuse," Yao said.

"I played a bad game, probably one of my worst games in a long time. I need to figure out what happened besides just thinking about those early fouls. I think I hesitated, worried about getting another foul. I think I moved not quick enough."

Even though Yao and Artest struggled, the cold shooting Rockets (39 per cent from the field) stayed close, after climbing out of a second quarter 16-point hole.

Allen ran off 11 straight points in the fourth quarter, helping the Celtics to a 101-97 advantage, but they couldn't seal the deal until the final seconds.

McGrady went up for a three-pointer and was fouled by Tony Allen with 10.3 ticks remaining. Though Rivers protested the call, claiming McGrady was trying to pass, referees awarded T-Mac three free throws.

"I know he was passing, there's no doubt about that, but it was a judgment call," Rivers said afterward. "It was a bad foul on our part. You can't foul a guy in that situation."

McGrady made two free throws, pulling the Rockets within 101-99, but Eddie House countered with two of his own at the other.

Houston got the ball to sharpshooting Brent Barry, whose three- point try fell well short of the mark, and Garnett grabbed the ball out of the air as time expired.

"We didn't play a complete game for the whole 48 minutes and you have to against that team," Rockets coach Rick Adelman said.

"We didn't play all that well, but we still had a chance in the fourth quarter. They're the best team in the league and we have to learn that, if we're going to get better."

Elsewhere:

Dallas Mavericks 98, San Antonio Spurs 81

German juggernaut Dirk Nowitzki scored 30 points, Jason Terry had 29, and the visiting Mavericks kept the Spurs winless through three games this season.

Josh Howard collected 14 points with 12 rebounds, while Jason Kidd contributed nine points with 10 assists and eight rebounds for Dallas (2-2) which rebounded from a 100-81 home loss to Cleveland on Monday night.

Frenchman Tony Parker netted 22 points while Tim Duncan had 19 with 15 rebounds for San Antonio (0-3) which matched its worst start since the 1976-77 NBA season.

Phoenix Suns 114, New Jersey Nets 86

Sharpshooting Raja Bell scored 22 points, including all six of his three-pointers, to lead seven players in double figures, as the visiting Suns scorched the Nets for their third win in four games.

Shaquille O'Neal scored 18 points, Amare Stoudemire added 14, while Steve Nash finished with 12 and 11 assists for Phoenix which shot a sizzling 63 per cent from the floor (43-of-68) in the blowout.

Vince Carter netted 19 points, while China's Yi Jianlian had 15 with eight rebounds for the Nets (1-2), who made just 34 per cent (28-of-83) of their field goal attempts.