Houston's Brian Hoyer was so bad he may lose his starting job.
Smith threw for 243 yards and three touchdowns in the first half as the Chiefs built a big lead and held on for a 27-20 victory over the mistake-prone Texans.
''We got the couple of turnovers in the red zone and were able to capitalize and I think in the end that was the difference,'' Smith said.
Travis Kelce caught two touchdown passes in the first quarter, the first one coming after Kansas City intercepted Brian Hoyer's first pass as a Texan.
Hoyer struggled in his Houston debut before Ryan Mallett took over with about six minutes left and led the Texans on two scoring drives to cut the lead to a touchdown.
Coach Bill O'Brien wouldn't say who will start next week.
''I don't know,'' he said. ''We'll review the film, and we will find out once we get into next week.''
Hoyer signed with the Texans in the offseason and beat out Mallett for the job in camp. After his first start in Houston, Hoyer was left fighting for the job once again.
''I'm disappointed and embarrassed,'' he said. ''I feel like I let those guys down and that's the worst feeling to have after a game. It'd be one thing if there was some fight back but that didn't happen when I was in there.''
Mallett deflected questions about whether he thinks he should start next week.
''Listen, I do what the coaches tell me to do,'' Mallett said. ''I'm going to do whatever this team wants me to do or needs me to do.''
Some things to know about Kansas City's win over the Texans:
BERRY IS BACK: Kansas City safety Eric Berry had two tackles in his first regular-season game since revealing he had lymphoma last November. Berry was declared cancer-free in June and cleared to practice just before camp.
WATT A DAY: J.J. Watt had two sacks, nine tackles and tied a career-high with six for losses. But he was disappointed that the defense was unable to stop Kansas City from scoring after the turnovers.
''In situations where we get put in a short field or something like that, it's our job to stand up and make a play,'' Watt said. ''And we didn't do that today.''
FILLING IN FOR FOSTER: Alfred Blue made his third career start in place of Arian Foster, who is out indefinitely after groin surgery and finished with nine carries for 42 yards. Jonathan Grimes and Chris Polk also got some carries neither of them could get the running game going either and Houston finished with just 98 yards rushing.
''We've got to do a better job,'' O'Brien said.
CLOWNEY RETURNS: Jadeveon Clowney, last year's top overall pick, had four tackles, with one for a loss, in his first game since microfracture surgery in December. He didn't start but came in on the second play and played mostly on third downs after the first series.
''I was just out there trying to help the team,'' Clowney said. ''Just getting a feel of it, my first time back out there in a while. I think it went pretty good for me.''
AP NFL website: www.pro32.ap.org and http://twitter.com/AP-NFL