AMES, Iowa (AP) - Iowa State quarterback Brock Purdy's eyes lit up when he saw a potential game-losing fumble floating aimlessly near the goal line.

The sophomore sprang into action, snapping up Sheldon Croney Jr.'s triple-overtime miscue and saving the Cyclones from a devastating defeat - even by their standards.

Croney Jr. scored from a yard out on the next play and 21st-ranked Iowa State rallied to edge past FCS school Northern Iowa 29-26 on Saturday.

La'Michael Pettway had a pair of touchdown catches for the Cyclones (1-0), who barely survived a massive upset after entering the year ranked for the first time since 1978. Northern Iowa (0-1), which was ranked 18th in the STATS FCS Preseason Top 25, was trying for 19th-year coach Mark Farley's 150th career win.

Croney fumbled just shy of the end zone on the second-to-last play of the game. But Purdy saw the ball bounce out, and he sprinted from the backfield to recover it at the 1 in perhaps the biggest play of his impressive young career.

''I saw who was underneath the pile, so I knew who would come up with it. Doesn't that tell you what he is about?'' Iowa State coach Matt Campbell said about Purdy's heads-up play. ''When I saw him there I thought we were going to be in great shape.''

For four quarters and nearly three extra sessions though, the last thing the Cyclones were in was great shape.

Iowa State had to settle for a 23-yard field goal from Connor Assalley with 59 seconds left in the fourth quarter simply to force overtime. Purdy had a touchdown run called back because of holding before that kick.

After the teams traded field goals in the first OT, Purdy found Pettway - a graduate transfer from Arkansas in his Iowa State debut - in the back of the end zone. But Northern Iowa pulled even at 23-all after freshman Will McElvain scrambled long enough to free up Trevor Allen for a 7-yard TD catch on a ball that travelled at least 40 yards.

Iowa State forced Northern Iowa into a field goal to start triple overtime, and Purdy completed three straight passes to set up a hectic finish.

''I don't know if the defense really saw it,'' Purdy said of his fumble recovery. ''I had probably the best angle on it. It was pretty scary. I'm not going to lie.''

The Cyclones were the second ranked team to win an overtime game against an FCS opponent. Auburn held off Jacksonville State 27-20 in 2015.

''That's why I love coaching in this game. It demands you being your best right out of the gate,'' Campbell said.

McElvain finished with 228 yards passing and a touchdown in his collegiate debut.

Purdy threw for 278 yards while completing 30 of 41 passes. Deshaunte Jones caught 14 balls, the second-most in school history, for 126 yards for Iowa State.

THE TAKEAWAY

Iowa State: Part of the Cyclones' struggles can be attributed to the fact that Northern Iowa isn't the least bit intimidated about driving about 100 miles southwest to play them. The Panthers even have three wins in Ames dating back to 2007. But Iowa State's offense, hurt by some questionable play calling, left a ton to be desired. The Cyclones also missed stars David Montgomery and Hakeem Butler perhaps more than anyone thought they would.

Northern Iowa: McElvain, a freshman from nearby Des Moines who was offered a walk-on spot by the Cyclones, looks like he's got a bright future. His scramble to find Allen in double OT was one of the best plays of the young season. ''Really talented guys who can run and escape, that's a challenge,'' Campbell said. ''As the game wore on, I thought you saw his athletic ability come forward.''

CYHAWK COINCIDENCE?

The last time a ranked team lost to an FCS school? That was three years ago when Iowa, the team Iowa State hosts in two weeks, fell to North Dakota State. But there's another connection to the rival Hawkeyes that the Cyclones can take solace in. In 2009, Iowa needed back-to-back blocked field goals to hold off these very same Panthers. That Hawkeyes team rallied to win the Orange Bowl that season. Iowa State's defense looked like it belonged on New Year's Day, but its offense at times looked like the first day of spring ball.

RUNNING BACK ROULETTE

Iowa State's muddled running back situation didn't get much closure in the opener. Johnnie Lang (14 carries for 60 yards) and freshman Breece Hall (11 for 47) shared the bulk of the carries until the fourth, when Croney was called upon. He found his stride, finishing with 56 yards on 13 attempts.

POLL IMPLICATIONS

It's very hard to imagine Iowa State maintaining its place in the Top 25 after that performance.

HE SAID IT

''All that work and all that time came to that ball laying on the ground and it was who came up out of that scrum,'' UNI's Farley said. ''It actually stopped for a second, and we all watched it sit there.''

UP NEXT

Iowa State has next week off. The Cyclones host No. 20 Iowa on Sept. 14.

Northern Iowa: The Panthers host Southern Utah on Sept. 7.

---

More AP college football: https://apnews.com/Collegefootball and https://twitter.com/AP-Top25

Copyright 2019 by STATS LLC and Associated Press. Any commercial use or distribution without the express written consent of STATS LLC and Associated Press is strictly prohibited.