From a study standpoint, it has been a unique week for Vikings defensive coordinator Alan Williams and his players as they prepare to head to Houston with hopes of defusing one of the league's most potent offenses.

It's not that the Texans do anything complex. But what they have assembled is a steady, balanced, minimal-error attack that can steadily suck the life out of an opponent.

That was obvious again last week as the Texans clinched the AFC South with a methodical 417-yard output in their 29-17 victory over Indianapolis.

First, it was Andre Johnson.

On the opening snap, the All-Pro receiver took a quick-hit pass from Matt Schaub and ate up 9 yards. On second down, with a play-action fake, Schaub again looked to Johnson, deep down the middle for an all-too-easy 52-yard gain.

Just like that, the Texans were in position for their first score, a 29-yard field goal by Shayne Graham that gave them the lead for good.

On Houston's following drive, Johnson capped a 13-play, 57-yard march with a 3-yard touchdown, continuing a day during which he caught 11 passes for 151 yards.

And then it was Arian Foster. Over and over again.

With a double-digit halftime lead, the Texans turned their workhorse back loose. And by day's end, Foster had 27 rushes for a season-high 165 yards, including second-half gashers of 31, 26 and 25 yards.

So how can Williams effectively allocate his resources when there's a big-time receiver to account for and a proven playmaker in the backfield as well?

"Always have 12 guys," Williams joked Wednesday.

While Johnson sparked things early last week, Vikings linebacker Chad Greenway said Houston gains its momentum from its ground attack, using a disciplined zone-blocking scheme that Foster reads well.

"When their linemen get to the second level and get to the linebackers who are cutting the backside off, that's when Foster has his cuts," Greenway said. "He can stay front side if the track is there. And if it's not, he cuts it back. ... When he's going downhill, he's as good as anybody in the league."

Williams is preaching the need to play "Viking football," a brand of fast and physical defense that thrives on big plays. That request has been fulfilled the past two weeks.

Sure, the Vikings surrendered 870 total yards in victories over Chicago and St. Louis.

But more importantly, they gave up only 36 points while creating four game-changing turnovers that provided 24 points.

Harrison Smith (against Chicago) and Everson Griffen (in St. Louis) each returned interceptions for touchdowns; Josh Robinson returned another pick to the Bears 5 to set up another TD; and Greenway's fumble recovery against the Rams provided another three points.

"When you score on defense, that's a big deal," coach Leslie Frazier said.

Such opportunistic play will be a much greater challenge Sunday against a Houston offense that has a league-low 13 turnovers.

"It's going to be on us to be patient, if they pick up a first down, not to panic," Williams said. "If they pick up a few yards, not to panic. And make them go the long haul."

Yet the Texans are equipped to do so with the efficiency of their running game, a patient quarterback in Schaub who rarely kills drives with mistakes and an explosive receiver like Johnson.

Williams raved Wednesday about the fluidity of Houston's ground attack with athletic lineman who work well together and play at a high speed. Foster then has big-play ability, evidenced by his 46 touchdowns the past three seasons.

"He can get to the edge on you," Williams said. "He has a great stiff arm and he runs with speed and power."

And if a defense focuses too heavily on Foster, Johnson owns 43 career 100-yard receiving games, five this season.

"There you go loading the box to try to stop the run and all of a sudden, there's Andre Johnson behind your secondary," Frazier said. "So you have to be careful. And you have to be smart about what you're doing."