DURHAM, N.C. — For all the penalty flags that flew in honor of Saturday night’s visitors from Notre Dame football — and there was a dozen of those totaling 70 yards — referee Riley Johnson’s ever-attentive crew never did get around to calling what seemed the most obvious infraction.

Too many men on the field.

Specifically, illegal cloning of nose tackles.

From start to finish in this 21-14 heist of a win over No. 17 Duke, the Irish had to be using at least three different versions of Howard Cross III.

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How else to explain the graduate senior’s sideline-to-sideline pursuit of Blue Devils quarterback Riley Leonard?

What other possible theories could there be for the epic production the stats crew credited to No. 56 in white?

Thirteen tackles. Three solo. Three and a half for loss.

Two forced fumbles. One quarterback hurry. And, just when dangerous Duke was firing up its heartbreak machine in the dying seconds, the clinching strip sack that jarred the ball loose from Leonard’s rugged grip and into that of Notre Dame linebacker Marist Liufau.

Did we mention yet that Cross played this game with a nasty sinus infection?

“I’m actually not going to touch anything,” Cross said with a hearty laugh and a satisfied glimmer as he sat at the postgame interview table.

It wouldn’t have been the first time Saturday that an encounter with Cross was hazardous to one’s health. Leonard, for instance, left the field on crutches after his persistent tormentor gave him one final pop.

And this, mind you, came one week after Cross played all but five snaps in a 69-play crusher of a loss at home against Ohio State. Those final two plays at the goal line, the ones Notre Dame infamously tried to survive with just 10 men on the field?

Cross was in for both plays, so maybe it was even after all.

A father's unspoken reminder: 'Keep moving'

Where does Cross find the energy?

“I’m not going to lie to you,” he said. “I have no idea. There were three or four plays where I was like, ‘I can’t breathe and I don’t know what’s going on.’ But I just kept going.”

Lesser competitors might have asked to skip a series or two, but not Cross. The young man from northern New Jersey could spot his family from the sideline.

Whenever he found himself wavering, Cross would grab a quick glimpse of a former Super Bowl-champion tight end who doubles as his unofficial sports psychologist. Each time he did, the younger Cross would find his mental tank had been replenished.

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“I looked at my dad in the stands, which I do every game,” Cross said, “and all I see is, ‘Keep moving. If you want to feel better, run it out.’ “

Generously listed at 6-foot-1 and 288 pounds, HC3 never stopped moving when the ball was live.

No matter how long it took the play to develop or how many loop-de-loops Leonard (6-4, 212 pounds) made on his way to an 88-yard rushing night, Cross kept his feet churning.

Howard Cross III: 'Fast-Hands Howard' Cross has been a hard-to-block revelation for Notre Dame football

“Howard Cross played relentless,” Notre Dame coach Marcus Freeman said. “Howard had a really good game.”

Notre Dame needed every ounce of its ailing nose tackle’s energy to pull this one out. Just as Cross led the Irish posse that finally subdued N.C. State scrambler Brennan Armstrong three weeks earlier in these parts, “Fast-Hands Howard” was right there in Leonard’s rearview mirror time after time.

The unspoken disclaimer: Objects in mirror are closer than they appear — especially those wearing No. 56 for Notre Dame.

“Like with any running quarterback," Cross said, "because I’m sure we’re going to see a lot the rest of the season, we practiced all week."

The coaching points from defensive coordinator Al Golden, defensive line coach Al Washington and the rest?

“(Leonard) will take off, so make sure you see,” Cross said. “If you’re going a certain way, this gap’s open, he’s probably going to take off. We just emphasized that. During the game there was just nowhere for him to go because we had eyes on him wherever he could have gone.”

From misery to ecstasy in one week's time

And at the very end, all eyes were on an “ecstatic” Cross, including those of the man who once wore No. 87 for Bill Parcells’ championship New York Giants. Howard Cross Jr. is 56 years old now, but the former 13-year NFL veteran can still impact the game merely through conversations with his son.

“My dad has always been the mental stabilizer for me,” Cross said in mid-September. “If I had a bad game, my dad would say, ‘Relax, they can’t block you. You’re blocking yourself.’ It’s like, ‘You can do it. You’re just telling yourself you can’t.’ Eventually I figured that out, and I have affirmations before the game.”

Late Saturday night, as he walked off the field for the final time, Cross could finally savor the accomplishment even if he couldn’t quite fill his lungs with air.

“There’s really no other feeling like it,” Cross said. “That’s what every guy who (plays) that position chases. It’s that feeling of everybody looking at you, everybody’s so proud of what you’ve done, and it just goes to show what we’ve worked on. It was a sum. I couldn’t have done what I did without the rest of my D-line.”

Nor could Sam Hartman and an injury-depleted offense have marched 97 yards to the winning touchdown without Cross and Co. forcing Duke to quick kick from the plus-33 with 2:35 remaining.

“That’s how great defenses are made,” Cross said. “When the chips are down and you don’t really know what’s going to happen, what are you going to do with the hand you have? We went out, we played our hearts out and when it mattered, we made the stop.”

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

This article originally appeared on South Bend Tribune: Analysis: Ailing Howard Cross III lifts Notre Dame football past Duke