Peyton Manning threw for 243 yards and two picturesque long touchdowns to Emmanuel Sanders, who returned from a nagging quad injury in electric fashion.
Von Miller, Montee Ball, and Kevin Vickerson made their preseason debuts, but Wes Welker departed with a concussion.
Welker was injured just before halftime, as Houston safety D.J. Swearinger was penalized for a forearm hit to the oft-concussed receiver's head.
For his part, Welker appeared to duck somewhat into the blow, so the fault appears not to lie entirely with Swearinger.
That's not how Manning saw it, however, as he got in the safety's face following his second long strike to Sanders. That prompted a rare (unprecedented?) taunting flag against Peyton.
Welker suffered two concussions in short order last season, causing him to miss the Broncos' final three regular season games.
Manning & Co. went into halftime with a 17-7 lead, but Houston accounted for all of the second half scoring.
Following a missed 36-yarder by Mitch Ewald, Tom Savage led the Texans on a 74-yard touchdown drive that ended inside the final minute.
Bill O'Brien mercifully opted to go for two, and Savage's successful conversion gave Houston the win, leaving both teams at 2-1 for the preseason.
- Videos: John Fox, Peyton Manning, Von Miller, and Marvin Austin speak after the game
- Mike Klis, Jeff Legwold, and Arnie Stapleton recap the game
- Joan Niesen, Mason, Troy Renck, and Paul Klee discuss Manning's harsh words for D.J. Swearinger
- Montee Ball, who received eight touches in short order, says he's been working overtime with Peyton after practice
- Andrew Mason and Klis revisit the goals they'd laid out for the team prior to the game