Texans CB Kareem Jackson intercepts Titans QB Matt Hasselbeck and returns it 63 yards for a touchdown. (US Presswire)

The Texans led 14-0 early, and the defense did the rest as Houston beat the Titans 38-14 to improve to 4-0 for the first time in franchise history.

Houston’s defense gave the Texans control of the game in the second half, forcing three turnovers. S Danieal Manning and CB Kareem Jackson returned interceptions for touchdowns, and a game that had the Texans feeling a little uneasy early in the second half turned into a route.

Tennessee (1-3) lost starting QB Jake Locker in the first quarter to a left shoulder injury when he was sacked by Texans S Glover Quin. Locker is scheduled to undergo an MRI on his left shoulder Monday, Titans coach Mike Munchak told 104.5 FM in Nashville after the game. Munchak didn't indicate if Locker suffered any structural damage.

The biggest positive for the Titans was the play of RB Chris Johnson. For the first time since Week 13 last year against Buffalo, Johnson rushed for more than 100 yards. He had 25 carries for 141 yards after managing just 45 yards on 33 carries all season coming into the game.

When the game turned: The Titans had the ball trailing 14-7 early in the third quarter. Titans backup QB Matt Hasselbeck dropped back to pass and threw down the middle for TE Taylor Thompson. Thompson deflected the pass, and it was intercepted by Texans S Manning, who returned it 55 yards for a touchdown.

Highlight moments: Texans QB Matt Schaub hit TE Owen Daniels for a 28-yard touchdown in the third quarter. Daniels took advantage of some poor tackling to take the ball into the end zone for a 28-7 lead. … Jackson provided the exclamation point in the fourth quarter. He dropped into zone coverage and read Hasselbeck. Jackson jumped in front of Titans WR Damian Williams for the interception and returned it 63 yards for a touchdown.

Top-shelf performances: Texans DE J.J. Watt -- 5 tackles, 2 sacks, 1 fumble recovery; Texans QB Schaub -- 20 of 28 for 202 yards, 2 touchdowns, no interceptions; Texans TE Daniels -- 6 catches for 72 yards and a TD; Texans RB Arian Foster -- 24 carries for 86 yards and a TD; Titans RB Johnson -- 25 carries for 141 yards. Titans QB Hasselbeck -- 17 of 25 for 193 yards, 2 touchdowns and 2 interceptions.

What they said about the two interceptions returned for touchdowns:

Manning to SportsRadio 610 after the game about dropping interceptions last week at Denver: “Coach got us on those jugs machines in practice. That paid off this week.”

Texans coach Gary Kubiak on Jackson’s season, according to Nick Scurfield of HoustonTexans.com: “The last three weeks, he's been exceptional. Really grown up as a player and as a person."

What they said about the play that knocked Locker out of the game:

Locker, according to the Houston Chronicle: “I didn’t see [Quin]. I would have done something if I had seen it.”

Numbers you should know: With Watt’s two sacks, he has had at least 1.5 in all four games this season. … The Texans were plus-3 in the turnover margin. Tennessee’s three turnovers led to 17 points for Houston. … Tennessee was penalized seven times for 73 yards and had a few costly penalties on special teams. A holding call on TE Thompson in the third quarter negated a 28-yard punt return by CB Darius Reynaud that would have put the Titans at Houston’s 30-yard line. Instead, Tennessee started at its 32, and Hasselbeck threw the interception to Manning that changed the game on the next play.

Injury update: Locker had to leave the game with a left shoulder injury. He separated that shoulder in Week 1 against the Patriots. … Texans RG Antoine Caldwell left the game in the second quarter with a right-ankle sprain. Caldwell is in his first year as a starter, but he and rookie Ben Jones have been rotating at right guard.

Going forward: Texans -- Houston has two primetime games. The Texans play at the Jets on Monday night next week before hosting Green Bay for a Sunday night game Oct. 14. Titans -- It doesn’t get much easier the next two weeks. Tennessee travels to play Minnesota, which is a surprising 3-1, next week. The Titans then return home to take on Pittsburgh on Thursday, Oct. 11.

Follow Texans blogger Sean Bielawski on Twitter: @CBSTexans.