HOUSTON -- They weren't learning a brand new defense, and as a whole they weren't trying to adjust to brand new coaches.

Because of that, Houston Texans defensive coordinator Romeo Crennel hoped his unit would pick up right where they left off last season, when they ended the season allowing fewer than 300 yards in each of their final four games. As it turns out there was a little bit of an adjustment period. The defense's second-half performance, though, offers hope that the rust they began Sunday's season opener with won't linger much longer.

Some things will have to change, though.

"We dug ourselves a hole early, and you can’t do that in this league," J.J. Watt said. "The teams are too good. I thought we fought back in the end, but much too little too late. And we can’t do what we did, especially in the first quarter, and expect to win too many football games in this league.

"I think if you look at the second half and the way that we came out there and battled, I think there’s signs of progress, but I mean this is the National Football League. We’re looking to go out there and win football games and not just show signs of progress."

J.J. Watt and the Texans' defense started to look as they were expected to look in the second half, but they want to figure out how to start games faster. AP Photo/David J. Phillip

To be clear here, the Texans' defense wasn't the primary reason the Texans lost Sunday's game. The offense struggled to move the ball and turned the ball over inside their own 15-yard line twice. That's tough to overcome. Special teams lapses led to poor field position even when turnovers weren't committed.

But this is a defense with the potential to be elite. It wasn't satisfied with how it played Sunday, and it shouldn't be.

The Chiefs scored on five of their first six offensive drives, though two were aided by Texans turnovers inside the Houston 15-yard line. The Texans defense did give up two drives of 83 and 66 yards leading to a touchdown and a field goal, respectively. The Chiefs used misdirection in some of their routes and relied on quick screen passes to keep the Texans' pass rush from getting to quarterback Alex Smith.

"No, not as much as they did," said Texans defensive end Jared Crick when asked if they expected so many screens. "Maybe after the success they had after the first few they figured they might as well keep trying it and keep trying it. They had success all the way, we couldn’t even stop them in the first half so we will have to shore that up. Other teams are going to be watching this and hit us with it next week so we have to shore that up."

Consequently the Texans allowed 27 points in the first half, matching the most they'd given up in a half last season. In fact, the Texans only averaged 9.5 points allowed per half last season.

The Texans forced four punts in a row after halftime and didn't give up a score in the second half. Had the offense experienced a similar transformation, the Texans might have won the game.

"I think we just went out with a better mindset," cornerback Kareem Jackson said. "We started fast in the second half and we were able to get off the field a little bit."

Many players and coach Bill O'Brien talked of heightened competitiveness in the second half. It's also fair to wonder if some rust came from the full unit never playing together in the preseason.

Whatever the reason for the slow start, the Texans defense showed progress in Week 1. They'll look to continue that next week.

"I think we have to learn how to start fast ourselves," nose tackle Vince Wilfork said. "Just looking at film from last year, training camp and preseason, that’s one of the things that we talk about a lot, so I think we have to put a lot more emphasis on that -- starting fast and being able to go out and compete early."