D'Ernest Johnson and South Florida racked up 629 yards in defeating Navy last week. (Joseph Garnett Jr./Getty Images)

The first indication of trouble for the Navy defense during its most recent game surfaced on the fourth snap from scrimmage, when South Florida quarterback Quinton Flowers ran through a gaping hole for a 63-yard touchdown.

On the Bulls’ next series, tailback D’Ernest Johnson eluded linebacker Micah Thomas and took off on a 23-yard touchdown run. Running back Marlon Mack scored from 85 yards on the one-play subsequent drive, and the Midshipmen were on their way to allowing touchdowns on South Florida’s first six possessions.

The 52-45 loss Oct. 28 in Tampa included the Bulls amassing 629 total yards, the sixth most Navy has yielded in program history, and converting their first 12 third-down attempts.

“We had a bad plan,” Navy defensive coordinator Dale Pehrson said.

In the immediate aftermath of allowing their most points this season, defensive players and coaches addressed breakdowns that the Midshipmen (5-2) had largely avoided during a two-game winning streak that had them up to No. 22 in the Associated Press rankings. Included in that conversation, Coach Ken Niumatalolo said, were frequent reminders about sure tackling.

But when practice began in earnest Tuesday, their attention was squarely on Notre Dame (3-5) and a second trip to Florida in just more than a week. Saturday’s neutral-site game, at EverBank Field in Jacksonville, will be the 90th installment of the longest continuous intersectional rivalry in college football history.

Navy is seeking to become bowl eligible for the fifth straight season and 13th time in 14 years. The Midshipmen last beat Notre Dame in 2010.

“Our tackling in the open field was an issue, but open-field tackling’s an issue in football now just from the standpoint of people spread you out, spaces are so big out there, and just trying to tackle people in space,” Niumatalolo said. “When you’ve got really good players like South Florida, it just compounds bad angles, not-proper-pursuit stuff.”

Notre Dame provides little variation schematically on offense from the majority of the Midshipmen’s opponents this season. The Fighting Irish’s base formation features spread principles, although their version has been nowhere near as prone to long gains or points as South Florida’s “Gulf Coast Offense.”

While the Bulls are ranked ninth in the country in scoring offense, averaging 43.4 points per game , Notre Dame averages 30.3 points (59th) and is ranked 63rd out of 128 schools in major college football in total offense (413.5 yards per game). The Fighting Irish managed 411 total yards in beating Miami, 30-27, last Saturday; South Florida racked up 464 yards of total offense against the Midshipmen in the first half.

“As long as we do our job like we’re supposed to, it gets shut down,” Navy defensive end Amos Mason said of facing spread offenses. “You can only go outside so many times until you have to start running inside.”

Notre Dame has labored in general this season running the ball and gained just 148 yards on the ground against the Hurricanes. The Fighting Irish average 149.8 rushing yards per game, ranking 94th nationally.

They’ve also had some instability at quarterback, with Coach Brian Kelly three weeks ago turning to backup Malik Zaire after starter DeShone Kizer threw two third-quarter interceptions in a 17-10 loss to Stanford. Kizer reentered in the fourth quarter to direct a drive to the Cardinal 8-yard line in the final seconds but fumbled on the last play amid heavy pressure, sealing Notre Dame’s fourth loss in five games.

Kizer played the entire way against Miami, completing 25 of 38 passes for 263 yards and two touchdowns. In last year’s 41-24 victory over Navy in South Bend, Ind., he went 22 of 30 for 281 yards , a touchdown and an interception, helping the Fighting Irish accumulate 459 total yards.

“They’re still Notre Dame,” Niumatalolo said. “They’ve got really, really good players. Brian Kelly is one of the best coaches in college football. That hasn’t changed. They’ve had some tough losses, but it hasn’t changed for us. We know who they are. It’s going to be an uphill battle for us.”