IOWA CITY - If you thought Donald Trump beating Hillary Clinton was the biggest upset of the year, you probably don't know what happened at Kinnick Stadium Saturday night.

Freshman Keith Duncan booted a 33-yard field goal as time expired as the Iowa Hawkeyes stunned the second-ranked Michigan Wolverines, 14-13, in a defensive slugfest before a festive sellout crowd of 70,585.

The Hawkeyes were shredded in their previous game at Penn State and looked like a team in deep trouble, but they put their hearts on the line Saturday and dented Michigan's shot at the national title.

Duncan turned and ran toward the other end of the field after his game-winning kick, with teammates and thousands of Hawkeye fans in hot pursuit. He was buried under a huge dog-pile and fortunately escaped unharmed.

"I just took off," he said. "I didn't really know what to do. You don't really practice these things. I was just running and then I saw the fans. That was pretty cool."

Iowa fans filled every spot on the field after the dramatic victory and celebrated with the Hawkeyes, many of whom lingered for more than 10 minutes before heading to the locker room. Security officials knew it was hopeless to try and keep fans off the field and did not bother to try, knowing it was peaceful gathering with nobody in serious danger.

Duncan had to dig himself out of the dog-pile, but came up smiling.

"It was an incredible feeling kicking that in front of 70,000 fans. I can't even speak right now," he said. "Kinnick has the best fans in the world."

Iowa Coach Kirk Ferentz does not let freshmen speak to the media, but the UI sports information department kindly interviewed Duncan on the media's behalf and delivered his words.

The Iowa defense, which played inspired football all night, forced Michigan to punt from deep in its own territory with about 90 seconds left in the game and the Wolverines clinging to a 13-11 lead.

Desmond King fielded the punt on his own 41 and ran for eight yards to the 49, but a Michigan player grabbed King's face-mask on the play for a 15-yard penalty that put the ball at the Michigan 36-yard line with 1:23 left.

Iowa quarterback C.J. Beathard hit Akrum Wadley with a 10-yard pass to the 26 and it began to look very good for the home team.

The Hawkeyes, who still had one timeout in their pocket, faced a 3rd-and-7 at the 23, which means they would have been looking at a 40-yard field goal into the wind if they did not gain another yard or get a first down, but then came the best call of the night.

Greg Davis, Iowa's offensive coordinator who has been criticized at times for his repertoire, called for a quarterback draw and Beathard ran eight yards to the 15-yard line.

Ferentz let the clock tick all the way down to three seconds before calling his final timeout for the game-winning kick. Michigan called a timeout to try and ice Duncan, but it didn't work.

"I had a feeling they would do it, but I wasn't thinking about it," he said.

The 165-pound rookie from Weddington, N.C., drilled it right between the uprights, setting off one of the biggest parties in Iowa football history.

It was like 1985 all over again, when the top-ranked Hawkeyes beat second-ranked Michigan, 12-10, on a last-second field goal by Rob Houghtlin in a game that pitted Iowa Coach Hayden Fry against Michigan's Bo Schembechler.

This time it was Ferentz against Jim Harbaugh and the Hawkeyes did it again.

Iowa's defense, maligned several times this year, held the mighty Wolverines to just 201 yards of total offense. The Hawkeyes finished with only 230 in the slugfest, but made them count.

Wadley excelled for the Hawkeyes, running for 115 yards with some terrific moves and catching five passes for 52 yards.

Iowa trailed 10-0 in the first half, but defensive tackle Jaleel Johnson tackled Michigan tailback De'Veon Smith in the end zone for a safety to make it 10-2 and switch the momentum. Iowa punter Ron Coluzzi, who had a terrific game with six boots for a 47-yard average, pinned the Wolverines with a 54-yard punt to the 2-yard line to set up the safety.

Iowa pulled within 10-8 on a nifty pass from Beathard to Wadley for a 3-yard touchdown on 4th-and-goal, another tremendous call by Davis from up in the press box. The Hawks missed the 2-point conversion on a catchable ball, but were squarely back in the game.

Iowa took an 11-10 lead on a 25-yard field goal by Duncan in the third quarter, but Michigan went ahead 13-11 on a 51-yard field goal by Kenny Allen with 9:35 left in the game.

It stayed that way until Duncan won the game, thanks to a perfect snap by Tyler Kluver and a perfect hold by Coluzzi that sent thousands of Iowa fans roaring into the night.