MINNEAPOLIS — The Minnesota Vikings have been waiting to show what they can do against a quality opponent.

The Pittsburgh Steelers showed them, all right.

Ben Roethlisberger ran for a touchdown and the Steelers defense scored a safety and held the mistake-prone Vikings to 25 yards of offense in the second half of an 18-3 victory Sunday.

The Vikings (8-6) rode a six-game winning streak into the game thanks to a big-play defense and a smart, efficient offense that rarely made mistakes against inferior competition.

Playing their first opponent with a winning record in seven weeks, the Vikings' offense wasn't up to the task.

The Steelers (9-5) pressured quarterback Brad Johnson all afternoon, forcing three turnovers and holding the Vikings to three points on four trips inside the red zone to keep pace with San Diego (9-5) for the last AFC wild card spot.

"Whenever they would seem to be getting any momentum, we stepped up and would silence the crowd," Steelers linebacker Clark Haggans said. "We just played hard and made plays when we had to."

The Steelers also blocked a field goal and got three of their own from kicker Jeff Reed to win their second straight after dropping three in a row.

"Everybody knows what is on the line," linebacker James Farrior said. "We did not have to do a whole lot of talking about it. Everybody knows the situation and that we put ourselves in a pretty good bind and we are trying to work our way out of it."

The Vikings' playoff hopes took a serious blow. After bouncing back from a 2-5 start, they now need a lot of help to catch Chicago in the NFC North or leapfrog Tampa Bay or Atlanta for the wild card.

"It doesn't make it any easier, obviously," coach Mike Tice said.

Nothing has come easy for this season for the Vikings, who were rocked by allegations of lewd behavior on a Lake Minnetonka cruise boat in October. On Thursday, four players were charged with misdemeanors, but the Vikings said they were focused on the game.

"That would be a lame excuse if I said it affected us," Tice said. "It did not."

They certainly played like it did.

The Vikings committed 13 penalties — 10 in the first half — and Johnson threw two costly interceptions in the red zone in an uncharacteristically sloppy performance by the veteran leader.

Johnson's first interception came on second-and-goal from the Pittsburgh 6, when his two-handed shovel pass glanced off Koren Robinson's shoulder and into the arms of Joey Porter.

After Roethlisberger dived into the end zone from 3 yards out for a 10-3 lead in the second quarter, Johnson drove the Vikings deep into Pittsburgh territory.

But they lost a chance to cut the lead when Johnson was hit by Porter and his ill-advised pass was picked off by Deshea Townsend in the end zone.

On their first possession of second half, Kimo von Oelhoffen blocked a Paul Edinger's 32-yard field goal try, and it was all downhill from there.

"We were in the red zone (four) times," Robinson said with a frustrated smile. "We have to find ways to score — get seven instead of three, get three instead of nothing. ... We still have to find a way to put up points to help the defense out."

Johnson finished 16-of-30 for 143 yards and two interceptions, looking more like a nervous rookie than the 14-year veteran.

Roethlisberger played that role on Sunday.

He was 10-of-15 for 149 yards and the rushing TD and didn't give the game away, as so many of the opposing quarterbacks have done against the Vikings in recent weeks.

Aside from a victory over the New York Giants, the Vikings other five wins during the streak came against teams with a combined record of 20-35 coming into the weekend.

Quarterbacks like Joey Harrington, Jeff Garcia, Charlie Frye and Ryan Fitzpatrick helped the Minnesota defense force 22 turnovers, including 17 interceptions, during that span.

"No turnovers. That's the biggest thing," Roethlisberger said. "Going through my head, it was, 'Don't turn the ball over. Be smart. If you don't see the clear picture, don't do it.'"

Notes:

Ed Hochuli's officiating crew had a busy day. The Steelers had 12 penalties for 129 yards for a grand total of 25 penalties for 224 yards. ... Willie Parker had 49 of his 81 rushing yards on one play in the third quarter. ... Tight end Jermaine Wiggins, tackle Marcus Johnson and center Melvin Fowler each left with second-half ankle injuries for Minnesota.