PHILADELPHIA, Feb. 6 (Ticker) -- Houston Rockets coach Jeff Van Gundy is a strong believer in stingy defense. On Monday, he watched his pupils execute his teachings to perfection.

Yao Ming scored 27 points and pulled down 12 rebounds as the Rockets posted their fourth straight win, a suffocating 87-81 triumph over the Philadelphia 76ers, who went more than 15 minutes without a field goal in the second half.

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Rafer Alston added a career-high five 3-pointers en route to 19 points for Houston, which posted its seventh straight victory over Philadelphia and has won 22 of the last 26 meetings in the series, including 11 of the last 13 in Philadelphia.

"It was great team defense," Alston said. Everyone was alert, aware and ready. We're starting to pick up our intensity defensively."

The Rockets, who have held five straight opponents under 90 points and nine of their last 10 under 100 points, pestered the 76ers into 33 percent shooting (24-of-72) from the floor.

"It comes from team defense," said Yao, who added two steals and a block. "We help each other together. We never leave a teammate (alone defensively). Our defense can change the way (an opponent) shoots the ball."

Allen Iverson shot just 6-of-22 from the floor but made 20-of-24 free throws, finishing with 32 points for the Sixers, who missed 19 straight shots spanning the final two quarters. Philadelphia did not make a basket in the final period until 65 seconds remained and the outcome was all but determined.

"We just struggled so bad offensively tonight," Iverson said. "Usually, it's the reverse. We struggle defensively and lose. Tonight, it was the total opposite. We just couldn't put the ball in the basket."

Alston also was a factor defensively on Iverson, collecting five of Houston's 16 steals.

"I was able to be active with my hands and I was able to come up with some steals," Alston said. "When (Iverson) brings (the ball) down, I was able to smack it down. I think those are the things that frustrate him."

The fourth quarter began in unimpressive fashion as neither team scored in the first 3 1/2 minutes until Yao converted a short hook in the lane and added a jumper for a 70-63 lead.

"I thought Yao played a strong fourth quarter," Van Gundy said. "We were having trouble scoring ourselves."

Houston extended the lead to 83-71 over the next five minutes behind back-to-back jumpers from David Wesley and Juwan Howard, a deep 3-pointer and a floater from Alston, and two free throws and a hook shot from Yao.

Philadelphia did not make a field goal in the fourth quarter until Iverson drove down the lane for a three-point play with 1:05 to go. Prior to that basket, the Sixers had not converted from the field since Andre Iguodala's reverse layup with 4:41 remaining in the third.

"Our offense was terrible," Philadelphia forward John Salmons said.

Sixers forward Chris Webber, who finished with 18 points and 12 rebounds, was dumbfounded by the 15:36 span between baskets.

"I don't think we've ever gone 19 straight field goals missed between 4:41 in the third and (1:05) in the fourth," said Webber, who also had a game-high seven turnovers. "Does the word 'aberration' (apply)? I can't see that happening again. It's sad that it happened tonight."

Houston originally took charge by closing the second quarter on a 23-5 run behind three 3-pointers from Alston and eight points from Yao to take a 44-36 halftime lead.

The Rockets extended the lead to 60-44 early in the third quarter before Iverson led Philadelphia on a 19-6 run to close out the period. The league's second-leading scorer, Iverson scored 10 points in the burst, connecting on 8-of-9 free throws.

Samuel Dalembert chipped in 17 boards and four blocks for Philadelphia, which finished with as many turnovers as baskets (24) in losing for the third time in four games.

"Our turnovers obviously were a big factor in losing the game," said 76ers coach Maurice Cheeks, whose team scored a season-low nine points in the second quarter. "We had 14 turnovers at halftime, but our offense went astray."

Meanwhile, the Rockets won despite being outrebounded by a 55-35 margin.

"It was part defense and probably (the Sixers) missing shots they couldn't make," Van Gundy said. "They killed us on the boards. We had to overcome that."

Tracy McGrady added 13 points but shot just 5-of-19 from the field for the Rockets, who improved to 13-6 with both McGrady and Yao in the lineup.

"When we have Yao and Tracy, we're a good team," Van Gundy said. "It's pretty simple."