SAN FRANCISCO -- Only 90 seconds into Sunday's prime-time showcase, the 49ers' 34-3 rout was on, courtesy of Tramaine Brock's 18-yard interception return for a tone-setting touchdown.

With Matt Schaub and the slumping Houston Texans making for easy prey, the 49ers (3-2) forced a season-high four turnovers and proudly posted a second straight prime-time win.

"This team is getting its confidence back," quarterback Colin Kaepernick said. "Our defense has played amazing, our offensive line played well, and we got a win."

The victory moved the 49ers (3-2) closer to the NFC West-leading Seattle Seahawks, who fell to 4-1 with a 34-28 road loss to the Indianapolis Colts. Two weeks ago, the 49ers lost to the Colts 27-7 and were bemoaning a two-game skid.

By returning to their signature defensive-minded, run-oriented form, the 49ers are now celebrating a win streak, and they're exhaling over a stretch that included facing 2012 playoff teams in four of their first five games.

"That's a tough schedule, but we're up for it. We're the 49ers," running back Frank Gore said. "We've just got to keep rolling, keep getting better, and then we can do whatever we want."

The 49ers now share second place with the Arizona Cardinals, who will visit Candlestick next Sunday. Then the 49ers take an extended road trip to Nashville (vs. the Tennessee Titans) and London (vs. the Jacksonville Jaguars).

Sunday night's winning recipe: Get Schaub & Co. to commit turnovers, run through the Texans' tough defense and play precise special teams.

"Just a lot of good things to point to," 49ers coach Jim Harbaugh said.

Brock accounted for two of the 49ers' three interceptions, and his pick-six came on an 18-yard return that extended Schaub's historic streak: four consecutive games of having a pass intercepted and returned for a touchdown.

"When I broke on the ball, I knew I had it," Brock said.

Said Schaub: "Everything just kind of snowballed."

That play sparked arguably the 49ers' best first-half performance since Harbaugh took over in 2011. Their 21-0 halftime lead matched their most-lopsided cushion under Harbaugh: a 24-3 lead Oct. 9, 2011, against the Tampa Bay Buccaneers in an eventual 48-3 win.

The 49ers defense matched its season total with three interceptions. Tony Jerod-Eddie made the third as an injury replacement for Ray McDonald, who left with a right-biceps injury.

Offensively, the 49ers got rushing touchdowns from Gore and Anthony Dixon, but it was Vernon Davis' 64-yard touchdown reception early in the fourth quarter that really finished off the Texans, who then benched Schaub in favor of T.J. Yates.

"When he hits full speed, there's really no one that's going to catch him," Colin Kaepernick said of Davis.

Kaepernick didn't attempt another pass after that scoring strike and set career lows as a starter: six completions, 15 attempts, 113 yards. His maligned counterpart, Schaub, was 19 of 35 for 173 yards with three interceptions for a 32.2 passer rating.

On Schaub's first pass, Brock broke off covering Keshawn Martin, picked off the pass intended for Andre Johnson and returned that theft 18 yards for a 7-0 lead.

It was the first interception this season by a 49ers cornerback. Brock was in the No. 3 role for a second straight game in place of Nnamdi Asomugha, who was sidelined again with a hyperextended knee.

The 49ers offense produced a 12-play, 65-yard touchdown drive on its first possession, capped by a 1-yard scoring run from Gore (17 carries, 81 yards).

Brock intercepted another Schaub pass intended for Johnson in the second quarter, and Brock's 13-yard return to the Texans' 32-yard line set up the 49ers' third touchdown shortly thereafter.

That third touchdown came on a 2-yard run by Dixon, which was preceded by a 14-yard run from Kaepernick and a 16-yard run by Gore, who injured his left ankle on an ensuing run for no gain before Dixon's score.

The Texans' fourth turnover came when Donte Whitner stripped Ben Tate in the fourth quarter. Whitner promptly fumbled, too, but Tarell Brown recovered, and that Texans turnover was converted into a 24-yard, Phil Dawson field goal for a 34-3 lead with 10:46 left.

The 49ers' shutout bid ended on the Titans' first series after halftime, via a 41-yard field goal by Randy Bullock.

What made the 49ers' second consecutive strong defensive display even more impressive was that it again came without two of the 49ers' stars: Patrick Willis (groin) and Aldon Smith (personal leave).

"They are starting to get hot again and starting to find their groove," Texans linebacker Brian Cushing said of the 49ers. "Anytime you play a team of this caliber at home, you have to make as few mistakes as possible and big plays, and we didn't."

For more on the 49ers, see Cam Inman's Hot Read blog at blogs.mercurynews.com/49ers. Follow him on Twitter at twitter.com/CamInman.

  • Offense remains problem for 49ers' next foe, the Cardinals. PAGE 3

  • McDonald leaves game after hurting right biceps. PAGE 4

  • Brock interception return sets tone for easy victory. PAGE 4