Chargers quarterback Justin Herbert, who had thrown just three interceptions in the regular season, threw four picks and was sacked four times in what was a disastrous display from the Los Angeles offense.
The Texans trailed by two field goals with less than a minute left in the first half, but then the momentum of the game shifted.
Texans quarterback C.J. Stroud fumbled a snap but recovered the ball and then scrambled to throw a 34-yard pass to Xavier Hutchinson.
On the next down Stroud made another big pass, connecting with Nico Collins on a 37-yard throw before ending the drive by zipping a 13-yard touchdown pass to Collins.
The Chargers were forced to punt on the next possession and Stroud took Houston 45-yards down the field to set up Ka'imi Fairbairn for a 41-yard field goal which sent the Texans into halftime with a 10-6 lead.
That ending to the half was a sign of things to come for the Chargers with the Texans getting out of a 2nd and 40 situation to enable Fairbairn to kick another field goal.
The decisive moment came when Herbert, trying to find Ladd McConkey, was picked off by Eric Murray who raced 38-yards into the end-zone to open up a 14-point lead for the home side.
Herbert threw another interception on the next play, with Derek Stingley returning the ball to the LA 13-yard line and the Texans adding another field goal.
Herbert gave his team some hope when he found McConkey down the middle and the rookie receiver raced away for an 86-yard score.
But incredibly disaster struck the Chargers again. Cameron Dicker's point after kick was blocked and the kicker attempted to bat the loose ball away saw D'Angelo Ross recover and sprint down to the end-zone for two points for the Texans.
Running back Joe Mixon, who put up 106 yards on the ground, then wrapped up the win with a 17-yard rushing touchdown.
Stroud threw for 282 yards and a touchdown with Collins putting up 122 yards on seven receptions.
McConkey had 197 yards on nine receptions while Herbert ended with 14 of 32 passes completed, 242 yards, one touchdown and four interceptions.
Ravens battle past AFC North foes Steelers
The Baltimore Ravens, fueled by a brutally efficient performance from quarterback Lamar Jackson and a fearsome running game spearheaded by Derrick Henry, beat the Pittsburgh Steelers 28-14 Saturday to launch their NFL playoff campaign.
Jackson completed 16 of 21 passes for 175 yards and two touchdowns. He also ran for 82 yards to supplement Henry's 186 rushing yards as the Ravens advanced to the AFC divisional round where they'll face either the second-seeded Buffalo Bills or the Houston Texans.
Jackson, a favorite to claim a third regular-season Most Valuable Player award who is seeking to shake a disappointing playoff history, threw two touchdown passes in the first half.
Henry added a rushing score to put Baltimore up 21-0 at halftime.
Baltimore drove 95 yards for a touchdown on their first possession, Jackson hitting Rashod Bateman with a 15-yarder for the score.
Then came a 13-play scoring drive that was all running plays - the last an eight-yard touchdown by Henry.
Jackson completed six straight passes on their final drive of the half, hitting Justice Hill with a five-yard scoring pass with two seconds on the clock.
The Steelers, who reeled into the playoffs having lost their last four regular-season games, got on the board in the third quarter when quarterback Russell Wilson hit Van Jefferson with a 30-yard scoring pass.
But Baltimore promptly responded, Henry powering 44 yards for a touchdown to make it 28-7.
Minutes later the Steelers clawed back another TD, Wilson firing a 36-yard pass to George Pickens who spun through the defense and into the end zone.
Wilson completed 20 of 29 passes for 270 yards but the Steelers, who reeled into the playoffs having lost their last four regular-season games, have now lost six straight post-season contests - a skid dating back to 2016.
Henry said the Ravens will remain focused on the ultimate goal - the Super Bowl on February 8.
"This is step one," he said. "We're going to enjoy this one and then get back to work. It's a great win, but we've got three more."