SOUTH BEND, Ind. — Notre Dame football coach Marcus Freeman took responsibility Monday for the goal-line breakdown that allowed Ohio State to run its final two plays, including a 1-yard run for the winning touchdown, against a 10-man Irish defense.

“There’s a whole bunch of systems in place to make sure that doesn’t happen, but ultimately it falls on me and that’s the reality of it,” Freeman said in the wake of Saturday’s 17-14 loss to the Buckeyes. “I’m not going to get up here and say this person should’ve done that (or) that person. Ultimately, I have to do a better job as a head coach to make sure those systems we have in place are executed.”

As part of that process, the 13^th-ranked Irish will have a new sideline signal when they meet No. 16 Duke on Saturday night in Durham, North Carolina. The signal will inform players on defense to purposely incur an offsides penalty that would force the officials to whistle the play dead.

“As we talked as a staff (Sunday), obviously we can’t let that happen,” Freeman said. “We know that. We can’t let 10 guys go on the field and not see it, but we came up with a call, a signal to be able to say, ‘Hey, you have to jump offsides and touch somebody on the offense so (the referee) can stop the play.’ “

Freeman wasn’t asked Monday why such a signal hadn’t already been put in place after a Game 2 mix-up against Tennessee State. In that scenario, however, the Irish had a timeout at their disposal.

Against the Buckeyes, Notre Dame burned its final timeout after getting a look at Ohio State’s second-down formation. Defensive tackle Gabriel Rubio and linebacker Jack Kiser were taken off the field during the timeout, but only nickel safety Thomas Harper was substituted into the game.

A subsequent incomplete pass for Marvin Harrison Jr. was thrown into the end zone against a 10-man defense, something Freeman admitted the staff didn’t realize in the moment.

Nor did the Notre Dame coaching staff notice when Ohio State subbed in 233-pound Chip Trayanum, which would have allowed the Irish to make a defensive counter before the Buckeyes would be allowed to start the play.

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“We as a coaching staff should be held to the exact same standard,” Freeman said. “We tell our players often, ‘Fight the drift.’ You can’t get caught watching the game. Everybody has a job to do on this play. Coaches have to win the interval too.”

Freeman cited the timing element and the ball’s placement on the far hashmark as reasons a last-second substitution wasn’t made.

“It was too late,” Freeman said. “By the time we realized it was 10 guys on the field, you don’t have time to get somebody from the sideline when the ball is on the 1-yard-line on the far hash. You have to touch somebody on offense to get them to stop the play. By the time we realized that, to run somebody out there you would have got a penalty, but (Ohio State) would’ve declined it and still scored a touchdown.”

An emergency scenario in which one of the Irish cornerbacks, Benjamin Morrison or Cam Hart, could have been directed from the sideline to grab one of the Buckeyes receivers before the snap might also have worked.

“It was a learning opportunity for myself and everybody involved with our program,” said Freeman, coming off his 19^th career game as a head coach at any level. “We all have to own that and make sure that never happens.”

Follow Notre Dame football writer Mike Berardino on social media @MikeBerardino.