The Rockets held a nine-point lead midway through the game on Saturday night but the Clippers fought back to earn a 107-94 victory and condemn Houston to their second home defeat of the season.
"We just stopped playing the way we had played to get the lead, and when you are playing against a team like the Clippers, they've been together a couple of years and play well together," Howard told journalists.
"We had to continue to do things that got us the lead, and we didn't do that tonight and they capitalized on it. They got a good road win."
Houston host the Toronto Raptors in their next game on Monday evening.