Let’s start with a positive.

Always accentuate the positive, right?

Bo Ruud returned a fourth-quarter interception for a touchdown. It helped save the day for Nebraska.

The play came out of a Cover-2 defense.

“The checkdown back released, and (the quarterback) threw a little floater,” Ruud said. “It was kind of one of those things I broke up on it. I wasn’t sure if he was going to tip it, so I kind of lost it for a second and bobbled it.”

Ah, but he caught it. Wrapped his arms around the darned pigskin and darted 34 yards to the pylon for a touchdown.

That breathed life into the Huskers, who cut Ball State’s lead to 37-35 with 9:21 remaining.

“We’ve been needing a big play for a while,” said Ruud, a senior captain and linebacker who has four career interceptions, two now for touchdowns. “It just gave everyone a little more confidence and changed the momentum.”

Said defensive coordinator Kevin Cosgrove: “Great play by Bo.”

Now, on to more pressing concerns.

Such as another overall meltdown by the Nebraska defense.

Nebraska won, 41-40, on the heels of last week’s 49-31 loss to No. 1 USC. For the first time in the history of Memorial Stadium, the Huskers have allowed at least 40 points in back-to-back home games.

Memorial Stadium was built in 1923.

“It starts with me,” Cosgrove said of the Blackshirts’ play. “I’ve got to look at it, and we’ve just got to do a better job.”

Saturday’s problems weren’t necessarily the same as last week’s. The tackling, while not spectacular, was somewhat improved from a week ago. Ball State didn’t create gaping holes in the running game as did USC.

No, this time it was an inability to contain a mobile quarterback and defend passes. Ball State quarterback Nate Davis threw for 422 yards against a Nebraska secondary missing senior cornerback Zackary Bowman, who was in street clothes with a sore hamstring.

“They got over the top of us,” Cosgrove said. “That can’t happen.”

Ball State totaled 610 yards.

Six hundred and 10.

“Absolutely, I take it personally,” Cosgrove said, “because I’m in charge.”

Cosgrove credited his defense for making key plays with the game on the line in the fourth quarter.

He pointed to a goal-line stand, after Ball State (2-2) had driven from its 30-yard line to the Nebraska 6 in three plays. (On its previous possession, Ball State needed all of two plays to go from its 4 to the Nebraska 22).

Linebacker Phillip Dillard stuffed two running plays, and Nebraska forced a scrambling Davis into an incompletion on third down, forcing a field goal.

“You can’t flinch. You can’t panic,” Cosgrove said. “I don’t want the kids to ever get an indication of that. You keep your poise and keep on coaching.”

There was senior linebacker Steve Octavien’s third-down pass breakup on Ball State’s final series … a play after Dante Love dropped a pass that was clearly destined for six points with 22 seconds remaining.

That was among three drops by Love, who still had 10 catches for 214 yards.

“We had to put a lot of effort into that fourth quarter,” Cosgrove said. “There was a lot of guys playing hard in there.”

Davis, who’d run for a combined 27 yards in three games, scrambled for 57 yards Saturday.

“He’s a guy that doesn’t want to run the football,” Cosgrove said, “but we were making him flush, and he saw some yards.”

So did running back MiQaule Lewis, who took a third-quarter toss to the left side, got a block and cut back en route to a 43-yard touchdown run. He wasn’t touched.

As for Davis’ arm? Very strong, as shown on his 58-yard TD pass in the third quarter to Love, who caught the ball at the goal line. Davis, as was the case throughout the day, had plenty of time to throw that ball. In 43 passing attempts, Davis was sacked once and hurried four times.

Defensive end Barry Turner said Ball State’s play-action game helped slow the rush.

“It’s hard for the D-line to adjust,” Turner said. “He’s on the roll. He’s not a slow guy.”

Cosgrove began the game with some blitz packages — Rickey Thenarse had a clear shot on Davis on one blitz and missed — but had to adjust.

“They were getting slide protection,” Cosgrove said, “so we went more coverage until the end.”

And in the end, Nebraska somehow prevailed — thanks in part to one positive play.

“I’ve been kind of out of the action, I felt like, the last few games,” Ruud said. “Teams have been, whatever they’ve been doing, it’s away from me, and I’ve been kind of getting anxious to make some plays.”

Reach Brian Rosenthal at 473-7436 or brosenthal@journalstar.com.