FLAGSTAFF, Ariz. — Riding high at 4-0, the Illinois State football team had not encountered a quarterback like Northern Arizona's Case Cookus nor a receiver such as Elijah Marks.
That step up in quality left the Redbirds feeling down and out Saturday at the Walkup Skydome.
Cookus hooked up with Marks for 124 first-half yards and Cookus totaled 380 yards overall through the air as the Lumberjacks throttled No. 7-ranked ISU, 37-16, before a crowd of 10,420.
"Disappointing all around," Redbirds coach Brock Spack said. "The first half we can't leave our defense out there that much, and they got a little wore down. But they didn't play that great either."
Marks exploited one-on-one coverage from Redbird cornerbacks, and Cookus later worked his tight ends into the equation against an ISU defense that had surrendered a total of 455 passing yards over the initial four games.
"We gave up some big passes," said Spack. "Their best receiver against our best DB (Davontae Harris), and they made some big plays and kept drives alive."
The ISU defense actually had Cookus on the run most of the opening half with a ferocious pass rush.
But Cookus snapped a 6-6 tie with a 32-yard touchdown pass to Marks down the right sideline with 29 seconds left in the first half to take a 13-6 lead.
"He's a tough guy. We got some good hits on him and got a couple sacks early on," Redbird defensive tackle Dalton Keene said. "They had a great game plan. We thought we had a great game plan. They outexecuted us for the most part and played great."
The Redbird offense mustered only first-half field goals of 32 and a career-long 51 yards from Sean Slattery. Northern Arizona countered with Griffin Roehler field goals of 30 and 42 yards.
The Jacks (3-2) knocked ISU on its heels early in the third quarter. Cookus rolled right and threw back left for a 23-yard touchdown strike to tight end Wallace Gonzalez.
"The second half I thought we were going to get back in the game. It seemed like the momentum changed," said Spack. "Then we make a dumb mistake, somewhere, some way, somehow."
The Redbirds did march inside the Northern Arizona 15 for the first time in the third quarter. But quarterback Jake Kolbe fumbled the snap from center on fourth-and-1 from the 9. Kolbe fell on the loose ball. Still, the Redbirds came up empty on a crucial possession.
Spack and Kolbe both called the fumbled snap a "miscommunication" with center Garrett Hirsch.
Northern Arizona extended its lead to 27-6 when Cookus tossed a lateral to Chance Brewington, who threw back to a wide open Cookus. The 2015 national FCS Freshman of the Year had several blockers escorting him on a 23-yard scoring reception.
Redshirt freshman Artiss Henderson offered ISU a wisp of optimism with an 83-yard kickoff return. But the Redbirds went backwards 4 yards on three plays and settled for a 38-yard Slattery field goal that banged off the right upright and caromed through.
ISU pierced the seal on the end zone for the first time since the first half of last week's win over Indiana State with a 15-yard Kolbe to Spencer Schnell touchdown pass at the 8:08 mark of the fourth quarter.
Kolbe passed for 223 yards, completing 25 of 45, and threw three interceptions.
"We got outplayed. That's a great team. They were better than us tonight," said Kolbe, who was sacked five times. "We've got to figure out what we did wrong, which is going to be a lot of stuff, and we've got to get better at it for Southern (next Saturday)."
Keene paced the Redbirds with 10 tackles, three for loss, and one sack.
"They put a full game together," Keene said. "We've got to put a full game together the next six weeks."