CEDAR FALLS (AP) &#8212 His team trailed 10-0, the offense was disjointed and Northern Iowa was puncturing his defense.

“There was a time I thought they might run us out of town,” Delaware coach K.C. Keeler said.

But the Blue Hens settled down behind quarterback Joe Flacco and the defense forced two critical fumbles, returning one for a touchdown as Delaware beat top-seeded Northern Iowa, 39-27, Saturday in the Football Championship Subdivision quarterfinals.

Flacco passed for 312 yards and two touchdowns, and Omar Cuff added 102 tough yards rushing and a touchdown for the Blue Hens (10-3), who will play Southern Illinois next weekend for the right to advance to the national championship game Dec. 14 in Chattanooga, Tenn.

“Early on, it didn’t look good,” Keeler said. “They were putting a lot of heat on us, and we were having a tough time stopping them. We just told them that, as coaches, we couldn’t help them. They manned up and got it done.”

Erik Johnson’s 55-yard fumble return for a touchdown in the second quarter help swing the momentum, and the Blue Hens converted 13 times in 20 third-down tries, often with Flacco scrambling to avoid a sack before finding a receiver.

Northern Iowa (12-1), which had been the last unbeaten team in the playoffs, got 150 yards rushing and two touchdowns from Corey Lewis and sacked Flacco five times. But the Panthers struggled much of the time after taking their 10-0 lead, and their defense couldn’t make the stops it needed to get off the field.

“The difference was the turnovers,” UNI coach Mark Farley said. “We did a good job initially, but we let it get away.”

Northern Iowa’s Eric Sanders completed 26 of 38 passes for 291 yards and a touchdown. But Sanders overthrew some receivers, failed to see some open receivers and often didn’t look like the smooth-operating quarterback who had completed 76 percent of his passes coming in.