Dan Persa threw for 318 yards and two late touchdowns before being helped off the field, and Northwestern handed No. 13 Iowa another devastating loss, beating the Hawkeyes 21-17 on Saturday.
Iowa (7-3, 4-2 Big Ten) can just about forget about a BCS berth. Its game against Ohio State next week just lost much of its luster, and once again, Northwestern (7-3, 3-3) spoiled the Hawkeyes' season, beating Iowa for the fifth time in six games.
Northwestern was trailing 17-7 after Ricky Stanzi threw for two touchdowns early in the third quarter, but an interception near the goal line by Brian Peters got the comeback started.
Persa led the Wildcats on an 85-yard TD drive, completing 7 of 8 passes and capping it with a 6-yard pass to Jeremy Ebert that made it a three-point game with 6:21 remaining. Iowa then punted and the Wildcats struck again.
A scrambling Persa capped a 91-yard drive with a perfect pass to Arby Fields, who beat Micah Hyde in the left corner of the end zone for a 20-yard TD. That made it 21-17 with 1:22 left, but while the Wildcats were celebrating, Persa was on the ground clutching his right calf even though he wasn't hit on the play.
Iowa had one more chance, reaching the Northwestern 39 with 26 seconds left after Stanzi hit Marvin McNutt with a 23-yard pass on fourth-and-15. Vince Brown sacked Stanzi for a 7-yard loss on second down, and after an incompletion, Peters and Hunter Bates broke up a desperation pass in the end zone.
Stanzi threw for 270 yards and Adam Robinson ran for 108 after missing last week's game against Indiana with an apparent head injury. But it was the same old story for Iowa against the Wildcats.
If one team has given the Hawkeyes fits lately, Northwestern would qualify.
Last year at Kinnick Stadium, the Wildcats spoiled Iowa's 9-0 start and national championship hopes while knocking out Stanzi with an ankle injury in a 17-10 victory.
A year earlier at Iowa, the Wildcats rallied from 14 points down and hung on to win 22-17 after Stanzi led Iowa to the 8-yard line late in the game.
Iowa managed just four first downs in the first half but appeared to be in good shape after scoring touchdowns on its first two possessions of the third quarter, turning a 7-3 deficit into a 17-7 lead.
Stanzi found McNutt in the right side of the end zone for a 5-yard TD that capped a 75-yard drive and put the Hawkeyes ahead.
They added to it when he found Derrell Johnson-Koulianos deep over the middle for a 70-yard touchdown on the next possession, making it a 10-point game. Johnson-Koulianos made the catch at the Northwestern 40 after he beat Jordan Maybin and turned toward the left sideline, reaching into the end zone before getting knocked out of bounds and drawing loud cheers from a large contingent of Iowa fans.
They were roaring again early in the fourth when Jeremiha Hunter intercepted Persa at the Iowa 38, but when Peters responded by picking off a deep pass near the end zone, the comeback was under way.