IOWA CITY, Iowa -- Penn State can't blame the BCS for this.

The Nittany Lions perfect season and hopes for giving coach Joe Paterno another national title were dashed by Iowa's backup kicker.

Daniel Murray, who hadn't made a field goal since the season opener, hit a 31-yarder with a second left and the Hawkeyes rallied to stun the third-ranked Nittany Lions 24-23.

All that talk about an unbeaten Penn State possibly being left out of the BCS national title game turned out to be premature. A third championship for the 81-year-old Paterno, who's had four unbeaten teams not win titles, is a long shot now.

Shonn Green rushed for 117 yards and two touchdowns, and Ricky Stanzi bounced back from an interception and a fumble to lead the Hawkeyes (6-4, 3-3 Big Ten) on their game-winning drive, which came after Daryll Clark threw just his third interception of the season.

Murray had lost the regular field-goal duties to freshman Trent Mossbrucker and was relegated to kickoffs. But with the winds swirling and strong, coach Kirk Ferentz opted for experience and Murray's strong leg.

He drilled it down the middle, sending Iowa's freezing fans spilling onto the field.

"I've always dreamed about it," said Murray, who grew up in Iowa City. "I kept hoping and hoping I'd get my chance."

The Nittany Lions were third behind Alabama and Texas Tech in the last Bowl Championship Series standings. They'll drop Sunday. The Big Ten title and a Rose Bowl berth are the Nittany Lions' main goals now.

"We need to keep our heads up. We can still have a heck of a year," said Paterno, who again coached from the press box and got around with a cane because of a sore leg and hip.

Iowa was down 23-14 heading into the fourth quarter. But Greene scored his second TD, from 6 yards out, to make it 23-21 with 9:20 left.

On the next possession, Penn State looked as if it got a break, when Iowa was called for a roughing the punter penalty that had the Hawkeyes seething. The Nittany Lions kept the ball and continued its time-consuming march.

But Clark made an errant throw down the middle that was picked off by Tyler Sash, who returned to Iowa's 29 with 3:46 left. Iowa then caught another break when Penn State was flagged for pass interference on third down, getting the Hawkeyes near midfield with a first down.

Stanzi, who was 15-of-25 passing for 171 yards, hit Derrell Johnson-Koulianos at the Penn State 15 with 18 seconds left to set up Murray's kick.

"I want to apologize to the whole Penn State nation for my game play today," Clark said. "I just keep having that turnover recurring in my head over and over. I can't get it out of my mind."