They Got After Joe Burrow
You have to be a good defense to win in the NFL. More importantly, you have to apply pressure to quarterbacks so you can help limit the impact they have on the game. If you can put your opposition quarterback into the ground enough times, the passing offense will fall apart.
Against the Cincinnati Bengals, the Texans were constantly in the backfield and got to Burrow four separate times, with long-time New Orleans Saints tackle turned Houston Texans tackle, Sheldon Rankins getting three of the team's four sacks. The Texans were unrelenting all game and Rankins' efforts helped embody that.
Sure, the Bengals' offensive line isn't great, an issue Burrow has faced since entering the league, but beating the teams you're supposed to be at is a key element of success in the NFL. So while the Bengals can't boast a great offensive line, the Texans still did what they needed to do and hopefully that gave some players some confidence to continue playing as well as they have going forward.
If they can get more guys going, like Will Anderson, who had a disappointing game, then the Texans' defense may be able to keep pace and maybe even out-shine the offense.