MINNEAPOLIS — The Minnesota Vikings kept their starting quarterback a secret until just before Sunday's kickoff.
Then Gus Frerrote, at least for this game, proved to be a capable backup for Daunte Culpepper.
Frerotte filled in for an injured Culpepper and threw for 267 yards and four touchdowns, three to Randy Moss, as the Vikings stayed unbeaten in four games with a 35-7 rout of the struggling San Francisco 49ers.
"Gus Frerotte came in and did exactly what we brought him in to do," said Minnesota coach Mike Tice, whose confidence in the 10-year veteran made it easier to rest Culpepper with three broken bones in his lower back.
Moss had eight receptions for 172 yards for the Vikings, who scored on four of their five first-half possessions, intercepted Jeff Garcia three times and held Terrell Owens to five catches for 55 yards.
"Nobody played very well," said 49ers coach Dennis Erickson, whose team has now lost three staright after an opening-day win. "You can go from me on down to everyone else on that sideline."
Culpepper was injured last week against Detroit, and Frerotte relieved him in a successful second half. He picked up where he left off, guiding the Vikings to a 28-0 halftime lead in a near-flawless performance.
"Whenever I'm in there, I'm going to be calm. Period. I think the guys feed off that," said Frerotte, who went 16-for-21 without an interception against a speedy San Francisco defense that entered the game second in the NFL in yards allowed with a league-high 13 sacks.
Deadpanned center Matt Birk: "What was his quarterback rating? 600?" (Actually, it was a franchise-best 157.2, just short of perfect.)
"Honestly, it's not a surprise to anyone in here," Birk said. "He's a cool customer."
The Vikings drove 72 yards on the opening drive, and Moss ended it by jumping over Ahmed Plummer to pull in a 15-yard TD pass from Frerotte, who signed with Minnesota in March.
Garcia was picked off by Corey Chavous, who ran the ball back to the San Francisco 38. The Vikings kept it on the ground the whole time, finishing with a 5-yard burst up the middle by Onterrio Smith.
Frerotte added touchdown passes of 35 and 22 yards to Moss and Nate Burleson before the half was over. He accentuated his record-setting afternoon with a perfectly-thrown 59-yard TD pass to Moss — who had another score nullified earlier for pass interference.
"I've played with some good receivers, but he's just a one of a kind," Frerotte said.
Garcia was awful: 11-for-23 for 108 yards, throwing several balls over and behind his intended receivers without much time to throw.
"My overall play needs to improve," Garcia said, "whether that's accuracy, whether that's making better decisions, whether that's getting us in better position to make positive plays."
Owens, who criticized the play-calling and pass protection in a post-game rant last week, stormed off the field after Kevan Barlow was stuffed for a 1-yard loss on fourth-and-1 at the Minnesota 31 late in the third.
Owens flung his helmet on the sideline and continued to scream. He was still frustrated afterward in the locker room — lamenting the Vikings' ability to involve their star receiver, Moss, while his team continued to struggle getting him the ball.
"Why wouldn't I want the ball?" Owens said. "Is that being selfish?"
The 49ers managed only four field goals in a 13-12 home loss to Cleveland last week, and their red-zone struggles were magnified on the opening drive of the second half.
After San Francisco marched 70 yards to the 4, Barlow ran for 2 yards on first-and-goal. Then Garcia threw three straight incompletions — passes intended for Owens, Tai Streets and Jed Weaver that were broken up by Vikings defenders — and turned the ball over on downs.
"We're frustrated," Owens said. "We want to win."
Notes: Tim Rattay played the fourth quarter, throwing a 37-yard touchdown pass to Streets to keep San Francisco from its first shutout since 1977. Garcia has a strained groin, but Erickson said the decision to pull him was based on the score. ... Chavous and Brian Russell each got their fourth interception of the year — career highs for both. ... Rookies Smith and Burleson scored their first career touchdowns. ... Warren Moon held Minnesota's previous single-game mark for quarterback rating, posting a 152.9 against New Orleans on Nov. 19, 1995. ... Barlow, who had 72 yards on 11 carries, left in the fourth quarter with a strained neck.