IOWA CITY, Iowa (AP) -- Iowa tossed Michigan State off the pile of unbeaten teams and turned the Big Ten race into a scramble for the Rose Bowl.
Ricky Stanzi threw three touchdown passes, and defensive backs Tyler Sash and Micah Hyde combined for a spectacular interception return score, as the 18th-ranked Hawkeyes stomped the fifth-ranked Spartans 37-6 on Saturday.
Adam Robinson added a pair of touchdowns for charged-up Iowa, which rolled out to a 30-0 halftime lead and dealt a crushing blow to the Spartans' national title hopes.
"Did we come unprepared? I don't think so," Michigan State coach Mark Dantonio said. "Did things snowball on us? I guess they did."
Iowa (6-2, 3-1 Big Ten) needed just 15 minutes to jump ahead 17-0, as Hyde dashed 66 yards after taking a pitch from Sash, who had picked off a pass.
Stanzi then found Robinson for a 32-yard TD pass, and Robinson's 2-yard touchdown run put the Hawkeyes ahead by 30 with 1:01 left in the first half.
Kirk Cousins threw three interceptions for the Spartans (8-1, 4-1), who were trying to move to 9-0 for the first time since winning a share of the national title in 1966.
Michigan State can likely forget about that this year. But the Big Ten title is still up for grabs and Iowa is in the middle of the race, too.
"I thought the guys came out ready at kickoff, certainly, and for the first time we really put it together in all three phases," coach Kirk Ferentz said.
It was the second time in three years the Hawkeyes ended a rival's unbeaten season at Kinnick Stadium. Iowa stunned then-No. 3 Penn State 24-23 in 2008 to boot the Nittany Lions out of the national title picture.
The win over Penn State was an upset that went down to the final seconds. This one was a blowout from the beginning - the biggest over a ranked team in Ferentz's 12 seasons at Iowa.
Iowa opened with an impressive 80-yard drive capped by a 3-yard TD pass from Stanzi to Colin Sandeman. Mike Meyer added a 37-yard field goal that put the Hawkeyes ahead 10-0 before the Spartans had a first down.
Sash and Hyde then teamed up for the play of the season for Iowa.
Sash jumped a route and picked off Cousins' pass at the Iowa 28. Sash immediately chucked the ball back to Hyde, who cut across the length of the field and stretched for the pylon at the end.
"I knew the route. I've seen it 100 times on film," Sash said. "I kind of just jumped up and tossed it to (Hyde) and he did the rest of the work."
That put Michigan State behind 17-0 for the second week in a row.
The Spartans kept their unbeaten season alive by rallying to beat Northwestern 35-27 - but this time it only got worse.
Stanzi's third TD pass of the day, a 22-yarder to Marvin McNutt midway through the third quarter, made it 37-0. Cousins finally got the Spartans on the board with a 6-yard touchdown pass to B.J. Cunningham to start the fourth quarter.
Stanzi finished with 190 yards passing as Iowa shook off a heartbreaking 31-30 loss to Wisconsin with by far its best performance of the season.
"If you look at Iowa today, we ran into a buzzsaw. Where they come off a loss and you could tell, they said 'We're not going to lose today. We're not going to lose at home, we're not going to lose two in a row,"' Cousins said.
Michigan State's performance was stunning, given both its ranking and the fact that the last three games between these teams were decided by a total of 12 points.
Michigan State never established the run, gaining 31 yards on 20 carries, and the Hawkeyes were able to sit back and wait for Cousins to force the ball.
Cousins was 21 for 29 for 198 yards, but he nearly doubled his interception total for the season.
"Sometimes you get caught up in the glamour of everything. Everybody's patting you on the back for being the No. 5 team in country, and sometimes it can get to you. We have to refocus and we'll be ready next week," Michigan State defensive tackle Jerel Worthy said.
Iowa defensive coordinator Norm Parker, who missed six games because of complications from diabetes and had his right foot amputated last month, returned to the booth in a wheelchair.
Parker wasn't involved with the gameplan save for a few tidbits, according to Ferentz, but his presence certainly didn't hurt. The Hawkeyes had given up 59 points in their last two games without him.
Michigan State got back defensive back Chris L. Rucker, who missed two games after serving eight days in jail for a probation violation. Rucker didn't start, but he entered the game in the second quarter - just in time to see the Hawkeyes jump ahead 23-0.
Dantonio declined to comment on Rucker after the game.
"I do think our football team will handle this. The reason I thought our football team was special, when I said this to them in February, was because we can handle adversity," Dantonio said. "That has to take place now."