Boston, we have a problem: Rockets, Celtics

It just wasn't the Celtics night tonight.

The magic number coming into this one was 100. Keep the Rockets under 100 and the Celtics would have a great chance to win. They didn't, and as a result, they fell to the Rockets, 101-89.

Once again, the Celtics' defense let them down in this one, and this is starting to become a concern.

Here's a recap:

The good:

* Rajon Rondo seemed to get things going in the right direction in the first quarter. He drove to the hoop for a layup, found Courtney Lee cutting along the baseline for a layup, and stole the ball from James Harden and led a fastbreak. After starting 2-of-8, Rondo finished 4-of-5 for a total of 6-of-13. He had 15 points, 4 rebounds, 13 assists, and 4 steals.

* James Harden only had 6 points in the first half. The Celtics limited him nicely. The second half, not so much.

* The Celtics had 15 steals tonight, which were the second-most they've had in a game all season.

The bad:

* The second half was an absolute train wreck for the Celtics defense. In the third quarter, the Celtics continuously turned the ball over leading to easy baskets. They were trading baskets with Houston that quarter, something you don't want to do with the third-best offense in the league.

* If the Celtics continue playing the way they have been, they will get run out of the gym by the younger teams in the league. Houston is in fact the youngest team in the league, and they built their early lead by pushing the ball up the court as quickly as possible. The older (and not to mention tired) legs of the Celtics were not ready for the Rockets.

* The first quarter has been a problem all year for the Celtics, and especially against a young team that likes to run, the Celtics need to be ready from the tip. There's no excuses for them to be flat and jogging back in transition.

* To attest to the up-tempo pace, Houston dominated the fastbreak points, 25-11.

* Kevin Garnett did not look good tonight. He still managed to get 15 points and to shoot 50%, but he started only 1-of-6. Garnett's plus/minus was a -9 tonight, very rare for the Big Ticket.

* Did anyone notice that Greg Smith was having the game of his life? For the most part, Smith got whatever he wanted. He made his presence felt down low, and he continued to cause problems for the Celtics' interior defense.

It only gets tougher for the Celtics. They take on the San Antonio Spurs tomorrow night, who own the second-best record in the West.