NBA.com's John Schuhmann is in Texas, following the Boston Celtics as they travel through the Texas Triangle.

HOUSTON, March 18, 2008 -- It was the unstoppable force against the immovable object. You can choose which one the Celtics were, but they're the one that won the battle. Decidedly.

The Houston Rockets' 22-game winning streak, the second longest streak in NBA history, is over. And it shouldn't be any surprise that it was the Boston Celtics who ended it. One night after coming back from 22 points down in San Antonio, the Celtics showed us that there is no doubt that they are the best team in basketball.

The Celtics did it with defense. They're the best defensive team in the league after all. While they took control of the game with a huge offensive third quarter (their 32 points were the most the Rockets have allowed in a third period all season), their defense was stifling all night, never allowing Houston to make a run.

It started with containing Tracy McGrady. The Rockets' star hit a few pull-up jumpers in the first quarter, shooting 3-for-7 and getting to the line twice in the opening 12 minutes. After that, the Celtics threw a blanket on him. In the final three quarters, McGrady shot 1-for-4 and never got to the line.

That's right. Four shots and zero free throw attempts in 36 minutes of basketball. And it's not like McGrady wasn't getting the ball. He had the ball plenty. But Tony Allen and James Posey were in his shirt all night.

"They just crowded him," Celtics coach Doc Rivers said. "We told them, 'He's gonna make shots on you. You can't get down on that. But just make him make tough, contested shots.'"

He didn't even do that. And it was because Allen and Posey had help. The Rockets like to free McGrady up with a high screen-and-roll, using one of their bigs. But the Boston bigs, namely Kendrick Perkins and Leon Powe, did not allow him to get free, keeping him contained up top.

"They just showed hard," Rivers explained. "We wanted Tracy, every time there was a pick-and-roll, to go away from the basket, and not turn the corner toward the basket. And I thought our bigs did a great job of showing. And then Tony and Pose fought through it to stay under."

"He's a good player and he likes to pull up," Perkins added, "so you gotta come up in almost a trap, but not really a trap, just a contain. And I think our guards did a good job on him tonight."

McGrady never got any space with which to operate. The Celtics forced him to get rid of the ball. And when you take the ball out of the hands of your opponent's best player, you're off to a good start.

But the defense doesn't stop there. Because if McGrady is occupying two defenders, someone else is open. And the Rockets have plenty of shooters to take advantage of being open. But the Celtics didn't allow them to stay open for very long. The other three defenders on the floor were factors as well, rotating and getting to the shooters before they could get comfortable. Houston was just 5-for-19 from downtown, and that includes Aaron Brooks' 2-for-2 in garbage time.

"I thought we did a terrific job of running them off shots," Rivers said. The Celtics didn't allow the Houston shooters to get in any kind of rhythm. But while containing McGrady and guarding the three point line are clearly priorities when you're playing Houston, the Celtics didn't change up their schemes just for this game.

"We really didn't change anything that we've been doing all year defensively," Paul Pierce said. "We show high on pick-and-rolls, rotate, help the helper, and that's pretty much it."

Pretty simple, except that there are 29 other teams who don't do it nearly as well. So, while you will note that Pierce and Kevin Garnett did their thing offensively and Powe (move over Ray Allen, there's a new member of the big three) scored 21 points (as sure of a sign there was that this was just their night), know that it was the Celtics' defense that won this game.

"I've never seen defense like that," McGrady said. "I mean, if they play defense like that night in and night out, then the NBA is in trouble, because that was defense at its finest."

Defense is why they're the best team in basketball, it's why they're the ones who ended the streak, and it's why you shouldn't be surprised if they're the ones holding the Larry O'Brien trophy come June.