HOUSTON - Carmelo Anthony was doubled over and wincing late in the first half before slowly walking off the court and into the locker room. And by the end of the game, all of the Knicks were hurting in a different way.

Back spasms ended Anthony's night with 1:45 left in the second quarter. The Knicks battled without him, but they had no one to carry them down the stretch and no one to stop James Harden.

Harden finished with 36 points and six assists and was responsible for the Rockets' last 19 points in their 91-86 victory over the Knicks Monday night at the Toyota Center. He scored their final 12 points and had three assists after the Knicks took a 78-72 lead. The Rockets then held them to eight points in the final 8:50.

Despite playing less than a half, Anthony led the Knicks (4-11) in scoring and was the only one in double-digits. He had 14 points and seven rebounds. His status for Wednesday night's game against Tyson Chandler, Raymond Felton and the Mavericks was unclear just after the game.

This was Anthony's first time at the Toyota Center since the free-agent negotiation period in July, when images of him in a Rockets jersey were displayed on the marquee outside the arena as hope filled the inside of the building. Now the Knicks are the ones hoping Anthony won't miss extended action.

Anthony revealed last week that his left knee has been bothering him since the second game of the season. This was the first mention of him having any back issues.

The Rockets (11-3) were without center Dwight Howard (right knee strain), starting point guard Patrick Beverley (hamstring) and starting power forward Terrence Jones (left leg nerve inflammation).

The Knicks trailed by 12 late in the first half but, without Anthony, enjoyed an 18-point swing. They led 78-72 after a three-pointer by Tim Hardaway Jr. with 8:51 remaining. But the Knicks scored only two baskets in the next 4:58.

After Iman Shumpert's runner tied it at 82 with 3:53 left, Harden buried a three-pointer. On Houston's next trip, Harden hit two foul shots to make it 87-82 with 3:07 left. Harden sank two more free throws with 1:13 remaining. Two more free throws by Harden put the Rockets up 91-82 with 41.9 seconds left.

This was considered somewhat of a reunion tour for Anthony. Houston and Dallas pursued him in free agency, and both teams are faring much better than the Knicks despite playing in a far better conference.

But Anthony took the near-max deal from the Knicks -- $124 million over five years -- and said he is not looking back and has no regrets.

"Of course I know that they're playing very well," he said. "It's not something that I kind of say to myself that I regret doing this or regret doing that."

Anthony bought into team president Phil Jackson's vision of how to build a sustainable winner, but the Knicks are off to a rough start, as expected.

Anthony said he doesn't allow himself to wonder what might have been. "No, I can't do that," he said. "I can't do that. I can't do that. That's just not my nature as a person. I would never be able to sit down and ask myself what if."

This was going to be a transition season regardless, especially with at least nine Knicks in the last year of their contracts. Jackson will try to build through free agency and trades.

The Knicks got off to a hot start, hitting 12 of their first 20 shots, and led 28-27 early in the second quarter. They went through another second-quarter cold spell, though, making only one of their next 13 shots.

The Rockets opened a 51-39 lead with 1:06 left in the half, but the Knicks hit six of their next seven shots and took a 52-51 lead two minutes into the third quarter.

Houston played sloppily in the quarter, committing seven turnovers in the first 6:40 and missing all four of its free throws. But the Knicks never led by more than two in the quarter, and the score was tied at 69 going to the fourth.