EAST LANSING, Mich. -- To stay undefeated, Iowa needed every last second and one perfect throw from Ricky Stanzi.
Stanzi connected with Marvin McNutt for a 7-yard touchdown pass as time expired and Iowa (No. 6 BCS, No. 7 AP) escaped with a 15-13 victory against Michigan State on Saturday night.
The Hawkeyes are 8-0 for the first time in school history and have sole possession of first place in the Big Ten at 4-0.
"It speaks to our players, the character that they have," Iowa coach Kirk Ferentz said. "They realized they still had time."
Iowa, sixth in the BCS standings, has won 12 straight dating back to last season, the second-longest streak in the nation.
Michigan State (4-4, 3-2) grabbed a 13-9 lead with 1:37 remaining when Kirk Cousins hit Blair White on a 30-yard touchdown. But the Hawkeyes stormed back with a sharp, game-winning drive led by Stanzi.
Stanzi hit Derrell Johnson-Koulianos with a 16-yard pass to move Iowa to the Michigan State 15. A defensive holding penalty wiped out an apparent interception -- upsetting a loud Michigan State crowd -- and moved the ball to Spartans 7.
Stanzi threw three incomplete passes in the end zone, but on fourth down with 2 seconds on the clock, he hit McNutt on a slant pattern in front of Michigan State defensive back Chris L. Rucker.
"He made a nice break inside, made a great grab," Ferentz said of McNutt.
Said Stanzi: "Obviously Marvin did a great job of getting open and the O-line did a great job of protecting."
Michigan State coach Mark Dantonio said he "couldn't believe" there were still 2 seconds on the clock before the last play.
"When we scored at the end, I thought that we had it," Dantonio said. "I'm proud -- not happy. Proud of the way our football team responded."
Adam Robinson had 109 yards on 27 carries for Iowa.
Cousins completed 16 of 32 passes for 225 yards for Michigan State.
The Hawkeyes last won a share of the conference title in 2004. Saturday's win keeps them in good position to win their first outright championship since 1985.
Road victories have been a key part of Iowa's success this season. The Hawkeyes staged come-from-behind victories at Penn State and Wisconsin, relying on a solid defense, good special teams and an offense that wasn't always pretty but came through in the clutch.
The same formula worked for Iowa against Michigan State, where it had lost four straight.
The Iowa offense was stymied until late. Stanzi finished 11 of 27 for 138 yards.
Iowa finished with 276 yards of offense.
Michigan State gained 310 yards, most of it through the air.
Michigan State had rebounded from a three-game September losing streak to win three straight in October and stay in the Big Ten race. But the Spartans could be scrambling just to get in a bowl game after Saturday's loss.
The Hawkeyes lost key players with injuries.
Iowa offensive lineman Dace Richardson went down with a leg injury in the first quarter. Hawkeyes safety Brett Greenwood was carted off the field midway during the third quarter after colliding head-to-head with teammate Tyler Sash in pass coverage.
Greenwood was immobilized before he was placed on the cart. He returned to the sidelines late in the game.