A competitive opener at No. 2 Ohio State didn’t lead to a Notre Dame victory, but it did leave the Notre Dame fan base bounding with optimism. The Fighting Irish didn’t topple Ohio State and earn the national respect the program believes it deserves after advancing to 2 College Football Playoffs and a national championship game during the past decade, but the they stood toe-to-toe with the mighty Buckeyes for 4 quarters, leading most the game before falling 21-10. As opening-day losses go, it didn’t dim spirits.

Instead, South Bend, Ind., was buzzing Saturday morning and well past noon. A “Who’s Who” of Notre Dame alumni dotted the campus, from Chris Zorich in a kilt and full Irish regalia to Fortune 500 CEOs. Saturday, a sun-splashed Notre Dame Stadium was ready to host a celebration, the initial win of what would become many for Notre Dame’s charismatic, compelling story of a young head coach.

Then the celebration turned into a catastrophe.

A tense, nervy opening quarter gave way to a 2nd quarter that saw Marshall, a storied program in its own right but at a smaller level and scale, take the lead on a 10-play, 79-yard drive in which the Thundering Herd dominated the Fighting Irish at the point of attack. Meanwhile, Marshall’s defense stymied the Notre Dame run game on the other side of the football, forcing Tyler Buchner to try and beat the Thundering Herd with his arm. Buchner, starting for just the 2nd time, couldn’t exploit Marshall’s mix of man and 2-deep zone.

By the time the sun started to disappear over the long horizon, Notre Dame found itself in deep trouble, down 4 points during the 4th quarter with little more than 5 minutes to play. That’s when Marshall delivered the death blow, intercepting a Buchner pass and taking it to the house to silence a still-believing Notre Dame Stadium crowd and send convert little Huntington, W.Va., from almost heaven to heaven.

Somewhat tellingly, it was Steven Gilmore, a future NFL corner somehow overlooked by Power 5 programs like Notre Dame, who sealed the Fighting Irish’s fate. Gilmore’s brother Stephon is an All-Pro corner, still plying his trade in the NFL, where he has been since he was a 1st-round draft pick out of Steve Spurrier’s version of South Carolina in 2012. The younger Gilmore, well, he stepped out of his brother and the late-afternoon Notre Dame shadows to leave his imprimatur on Saturday’s game, leaving Notre Dame soul-searching in the process.

If you are hoping on this fine late-summer Monday to find that Saturday was just a nightmare, think again.

After just 2 games, Notre Dame has gone from top-5 CFP hopeful to gut check. That it happened in a blink is stunning; that it happened 3 games into the Marcus Freeman era at Notre Dame is scary.

Scary or no, such is the state of things for the Fighting Irish, who still are searching for Freeman’s first win as a head coach. Freeman, who played under high expectations as an All-Big Ten linebacker at Ohio State and who moved like a meteor through the coaching ranks to land one of the best jobs in football at 36, was accountable, which is a start.

“It’s disappointing,” Freeman said, his tones a bit more hushed than after the Ohio State defeat. “We didn’t execute. It comes down to execution and we did not execute the way we obviously needed to in order to win this game. We have a lot of — we have to look at ourselves as individuals. I told the team that. We all have to look at ourselves, starting with the head coach on down and say, “OK, what do I have to do? What do we have to do to fix the issues we’re having, and not just focus on the end result?’ We have to look at the lack of execution in all phases of our team and where we can improve.”

If there were a definition for “gut check” in old Mr. Webster’s book, it would sound, you would think, like Freeman’s statement to the press Saturday evening.

As for what went wrong, well, where to start?

It’s a line-of-scrimmage game, and Notre Dame was manhandled on both sides of the line of scrimmage. The strength of this team was supposed to be a more-experienced, talented offensive line and a defensive front with multiple NFL prospects. That might end up being the case during November, but both units have been outplayed in Notre Dame’s 2 games. Marshall, often running right at NFL 1st-round prospect Isaiah Foskey, collected 219 yards on 50 carries, with 163 coming from Khalan Laborn, who looked more like Marshall legend Ahmad Bradshaw than a journeyman whose career had never quite lived up to his 5-star billing. Laborn, you might or might not recall, began his career as a top-30, 5-star recruit at Florida State, only to enter Saturday’s game with just 399 career rushing yards.

On the other side of the ball, Jarrett Patterson’s injury continues to haunt the Fighting Irish. But even with Patterson banged up, shouldn’t Notre Dame be able to manage more than 3.5 yards per carry against Marshall? If that type of production continues, the path to 0-4 is clear.

The quarterback also has to be better.

Time and again Saturday, Buchner missed throws where offensive coordinator Tommy Rees had schemed players open. A deep seam route to Lorenzo Styles was thrown over the wrong shoulder, and Styles couldn’t corral it, despite curling his body in the air to nearly pull it in. A 4th-quarter slug concept found Kevin Bauman wide open for what would have been a take-the-lead late score. Buchner overthrew him by 5 yards. Missing the open throws, and making poor ones, like Buchner’s 2 interceptions, put the Fighting Irish defense in holes it couldn’t, at the end of the day, wash away, despite a game effort, especially from the linebackers, who are a point of strength.

Buchner is now out for the season, injuring his AC Joint late in Saturday’s game. Drew Pyne, a more natural passer than Buchner, will take over, but regardless of who is under center, Notre Dame will need playmakers around them to make life on the new starting quarterback easier. That begins with the Fighting Irish’s best playmakers, including the electric Chris Tyree, who has just 65 yards on 12 touches through the season’s first 2 games, must find ways to make an impact. Notre Dame’s offense is simply not good enough to drive the length of the field consistently. Explosive plays are going to be vital to avoid future calamity.

The good news is there’s no bye week to sit and stew. An unbeaten Cal team from the Pac-12 will visit Saturday (2:30 p.m. ET, NBC). It will be chance No. 4 — as in leaf clover — for Freeman to get win No. 1.

Perhaps the gut check will help the Fighting Irish finally deliver.