STATE COLLEGE - With his team pinned against the goal line and faced with the prospect of punting from the back of its own end zone, Iowa coach Kirk Ferentz knew that giving up a safety meant putting Penn State within a field goal of victory.

Without hesitation, Ferentz called for the safety and turned the game over to his defense.

"They've earned that confidence," Ferentz said.

No doubt.

Since back-to-back losses to Arizona State and Michigan, the No. 23-ranked Hawkeyes (5-2, 3-1 Big Ten) have given up only 27 points in three games, including holding Penn State's offense scoreless in a 6-4 victory Saturday over the Nittany Lions (2-5, 0-4).

All of Penn State's points came off safeties, the first when the snap went over punter David Bradley's head, the second - the intentional safety - when the Hawkeyes were called for holding in the end zone.

"That really made us feel like they had confidence in us going out there and making plays," said cornerback Jovon Johnson. "That safety, we wanted that to happen because we knew that if they were going to leave it up to us, we were going to go out there and get the victory."

They did it with an aggressive, but disciplined defense that stifled every aspect of the Penn State offense:

The Penn State passing game that came alive against Purdue - Zack Mills went 29 of 51 for 293 yards in that game - sputtered against Iowa. Mills finished 7 of 19, and Michael Robinson went 2 of 9; they combined for just 96 passing yards.

Each of Iowa's starting defensive backs intercepted a Penn State pass. Mills and Robinson threw two interceptions apiece, and Penn State fumbled three times, losing one.

The Nittany Lions had just 51 rushing yards on 29 carries, and Tony Hunt's 12-yard run in the fourth quarter was Penn State's longest of the game.

"We take great pride in not allowing the rushing game to get started," defensive end Matt Roth said.

Penn State, too, had a solid defensive performance. Kyle Schlicher kicked two field goals for the Hawkeyes, but only one was a result of offense; the other came after a 53-yard interception return.

But the difference between the two was that Iowa made the big plays when it needed to. When a blocked punt in the third quarter gave the Nittany Lions a first-and-goal on the Iowa 9-yard line, the Hawkeyes gave up just one yard in three plays. Robbie Gould's field goal try for the Nittany Lions went wide right.

When Penn State drove to the Iowa 9 in the fourth quarter, Antwan Allen picked off a Robinson pass at the 1.

"I think that our defense was making them shoot themselves in the foot by getting pressure on the quarterback, making plays on the ball, and most of all stopping their bread and butter, the run," Johnson said.

It's a far cry from where the Hawkeyes were one month ago, when they gave up 435 passing yards and 44 points to Arizona State.

"I told our whole football team after that ball game, hopefully down the road we can just throw that one out and say it was an aberration," Ferentz said. "We won't be able to say that until the season's over."