ESPN College Football

EVANSTON, Ill. -- Dan Persa's last pass of the season gave Northwestern it's biggest victory of the year.

The Wildcats' star quarterback connected with Demetrius Fields on 20-yard TD pass to with 1:22 to play, then ruptured his Achilles' tendon when he started running to join his celebrating teammates. Persa accounted for all three Northwestern touchdowns in a 21-17 victory Saturday that dealt a severe blow to No. 13 Iowa's Big Ten title hopes.

Fast Facts

• Northwestern continues to be Iowa's kryptonite, winning five of the last six meetings.

• Iowa coach Kirk Ferentz has a losing record against only two Big Ten teams -- Northwestern and Ohio State. Iowa hosts Ohio State next week.

• Northwestern overcame its second-half woes; the Wildcats blew leads of at least seven points against Penn State, Michigan State and Purdue this season to lose, but they came back after blowing a seven-point lead in this one.

• Northwestern QB Dan Persa topped 300 yards passing for the fourth time in his career, all have come this season.

• Iowa entered with a plus-12 turnover margin on the season but was even in this game, including a interception by Ricky Stanzi -- only the fourth interception Iowa has thrown all year.

-- ESPN Stats & Information

The injury will end Persa's season.

"He'll be back and ready to for his senior year," coach Pat Fitzgerald said. "When you look at the first chapter for him as a full-time starter, it's pretty impressive. One thing I know about Dan is he won't be satisfied, No. 1. No. 2, you better look out because he's going to come back."

Persa threw for 318 yards and capped an 85-yard TD drive with a 6-yard pass to Jeremy Ebert with 6:21 to go to bring the Wildcats within three. The touchdown throw to Fields completed a 91-yard drive, but Persa never even reached his joyous teammates.

Persa was on the ground, holding his right leg. He was helped to the sideline and several of his teammates circled the table he was on to keep TV cameras away.

Persa was scheduled to undergo surgery later Saturday.

Iowa (7-3, 4-2 Big Ten) is now a long shot to win the Big Ten and its home game against Ohio State next week just lost much of its luster. Again Northwestern (7-3, 3-3) played spoiler to the Hawkeyes, beating Iowa for the fifth time in six games.

"The Big Ten race, obviously we're out of that," quarterback Ricky Stanzi said.

And for that, he was blaming himself.

Northwestern was trailing 17-7 after Stanzi threw two touchdowns passes early in the third quarter. An interception near the goal line by Brian Peters got the Northwestern comeback started.

But Wildcats tight end Drake Dunsmore said it was a "bittersweet" afternoon.

Persa's injury is a huge blow, considering he supplies almost all the offense whether he's throwing the ball or running it. Now Northwestern will turn to Evan Watkins, a 6-foot-6 freshman.

Iowa had one more chance after the go-ahead touchdown, 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. After an incompletion, Peters and Hunter Bates broke up a desperation pass in the end zone, setting off a wild celebration with fans pouring onto the field.

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.

They have given the Hawkeyes fits lately.

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 Northwestern 8 late in the game.

Now this.

"Today, they just outplayed us," Iowa coach Kirk Ferentz said. "If you look at [Northwestern's] season from the past two years, they've had two good football teams. They've played extremely well against us."

Iowa managed four first downs in the first half but appeared to be in good shape after Stanzi threw for touchdowns on the first two possessions of the third quarter, including a 70-yarder to Derrell Johnson-Koulianos that made it 17-7.

Hawkeyes fans let out a roar and they were at it 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 it changed everything.

"The interception cost us the game," Stanzi said.