Pittsburgh defensive back Pat Amara Jr. picks up Pitt's blocked punt against Iowa and runs it in for a touchdown to tie Iowa at 17 in the third quarter. (0:29)

IOWA CITY, Iowa -- The debate over whether icing a kicker actually works has been raging in college football for decades.

Pittsburgh coach Pat Narduzzi gave detractors of the practice more ammunition -- while Iowa's Marshall Koehn gave the Hawkeyes one of their most thrilling wins in years.

Koehn kicked a 57-yard field goal as time expired to push Iowa past Pittsburgh 27-24 Saturday, giving the Hawkeyes their first 3-0 start in six years.

"Obviously we would have liked to get it a little closer," Iowa coach Kirk Ferentz said. "As it turned out, it didn't matter. What an unbelievable kick by Marshall. Just tremendous composure."

C.J. Beathard had 258 yards passing for Iowa, which drove 31 yards in under a minute to set up Koehn's winning kick.

Tyler Boyd's 8-yard TD catch with 52 seconds tied the game at 24-all for Pitt (2-1).

Narduzzi called timeout to ice Koehn, who got off a kick that was well short anyway. Pitt then put a returner in the back of the end zone for Koehn's next effort.

But Koehn's second try was so strong that it appeared to have room to spare.

Koehn is now 4 for 4 on field goals this season -- all from at least 40 yards out.

"I kicked myself in the butt at the end," Narduzzi said. "That's what everybody does. You've got a timeout on the board, you're going to use it and try and freeze him a little bit. Obviously he's got ice in his veins I guess."

Nate Peterman had 219 yards passing and two touchdowns in his first start for Pitt (2-1), and Boyd had 10 catches for 131 yards.

Iowa controlled the first half, going ahead 17-7.

But midway through the third quarter, Pitt got the play it needed from Ryan Lewis and Pat Amara.

Lewis blocked Dillon Kidd's punt attempt and Amara did the rest, running it back 28 yards to pull the Panthers even at 17-all.

For the second straight week, the Hawkeyes had a fourth-quarter rally in them.

Iowa answered with a key defensive stop, aided when the Panthers chose to punt from the Iowa 42 on 4th down and inches. The Hawkeyes then went 80 yards to retake a 24-17 lead with 6:04 left.

Peterman, a Tennessee transfer, responded for his new team. He converted a 4th down and 15 with 1:28 left on a 19-yard pass to J.P. Holtz before Boyd's touchdown catch.

Seeking a spark, Pitt started Peterman over Chad Voytik -- who had opened 15 consecutive games -- along with freshman Darrin Hall at running back.

Peterman threw a pair of picks to Iowa's Desmond King in the first quarter, and Beathard's 9-yard run gave the Hawkeyes an early 10-0 lead.

But a Panthers pick of Beathard got them back in it, as Scott Orndoff's 15-yard TD grab from Peterman on the next play to make it 10-7 Iowa with 10 minutes left in the first half.

The Hawkeyes closed the first half with a 4-yard Jordan Canzeri touchdown run to jump ahead 17-7.

"It's a game of inches, and we didn't get the inches at times that we needed to," Narduzzi said.

Pitt would rally behind a physical defense that resembled Narduzzi's units when he was the defensive coordinator at Michigan State and, presumably, a new quarterback.

But Beathard picked up a first down with his legs with two seconds left, giving Iowa a slim chance at a win.

"It was a great effort on his part. All night long, he played a tremendous football game," Ferentz said of Beathard.

Koehn converted, giving the Hawkeyes their first 3-0 start since they went 11-2 and won the Orange Bowl following the 2009 season.

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AP College Football website: www.collegefootball.ap.org .