Jared Allen had a couple of opportunities to show off his calf-roping technique to the Metrodome audience Sunday. This came after he forced a fumble with a second-quarter sack and then had another sack with 92 seconds remaining to take away Houston's last gasp.

Allen was asked after the Vikings' 28-21 victory if his postsack pantomime of roping a calf has received NFL approval.

"Nah ... this is America," he said. "What kind of a country would this be if you can't tie up a calf?"

The acquisition and signing of Allen before the April draft had triggered a degree of optimism for the Vikings that had been missing for several seasons.

They had Adrian Peterson to lead the league's best rushing game, and they had Allen, the league's best pass rusher, to further invigorate the defense. This brought the giddiness back to Mankato this summer when the Vikings assembled for training camp.

And then came the regular season: two months of uninspired play that left the Vikings at 3-4. It was so disappointing that, for a few hours last week, it looked as though the Twin Cities' primary football focus could be shifting to the Gophers.

And then came the weekend: On Saturday, the Gophers looked at opportunity and flinched, as had been the case so often with their predecessors.

Sunday, the Vikings messed around long enough in the third quarter to put Houston back in the game, and then they turned loose the superstars -- Allen and Peterson -- and the customers were in a fine mood as they left the Dome.

Next weekend, we get another home doubleheader and our little football world will be back to normal: The Gophers and the worst Michigan team in more than 40 years will be the preliminary, and the Vikings and the Packers will be the main event.

A sense that it was OK for fans to start feeling optimistic again about the Vikings didn't take hold until Peterson popped a 40-yard run to start a possession late in the third.

He had 19 carries for 49 yards before that run. The next three carries were good for 83 yards. Once he started ripping the Texans, Gus Frerotte was able to hit a wide-open Visanthe Shiancoe for a 25-yard touchdown that made it 28-14.

Allen and his colleagues up front were hounding the Houston quarterbacks, Matt Schaub and Sage Rosenfels, for most of the afternoon. Unfortunately, the gents in the secondary concentrated on stopping Andre Johnson and gave the rest of the Texans' receivers more leeway than a political ad.

Rosenfels replaced a limping Schaub at halftime and threw for 224 yards in the second half.

"He was getting the ball out pretty quick," Allen said. "I don't want to say we were confused, but we did let him go down the field a couple of times."

A big rush by Ray Edwards gave the Vikings a stop early in the fourth quarter when it was 28-14. Rosenfels led his second touchdown drive on the next possession.

The Vikings recovered an onside kick and then Chris Kluwe punted to the 10, leaving the Texans with 1:58, zero timeouts and 90 yards to travel.

"We knew what to do," Allen said. "Sack the quarterback. That's how you put an end to the two-minute drill."

The Texans gained 8 yards on first down with the 11th completion of the day to tight end Owen Daniels. On second-and-2, Allen reached around a blocker and threw down Rosenfels with one hand for an 8-yard loss.

He roped the calf, and then Kevin Williams led a charge that submerged Rosenfels at the 2. Game over.

Allen was credited with two sacks, a forced fumble and two hurries. His relentless attack overwhelmed rookie Duane Brown, and Ephraim Salaam, an 11-year veteran, was back in the game at left tackle.

Randall McDaniel, the all-time great offensive lineman, was sitting in the stands.

"Allen had beaten on that kid all day, but I told my friend when they pulled the rookie, 'This is going to get ugly now,' " he said. "There's nothing worse for an offensive lineman than ... running into a guy like that -- a great player who's all revved up and looking for sacks."

Patrick Reusse can be heard weekdays on AM-1500 KSTP at 6:45 and 7:45 a.m. and 4:40 p.m. preusse@startribune.com