The 15 points by Johnell Davis were big. So, too, the clutch 3-pointers by Michael Forrest during Florida Atlantic’s second-half run.

But the most decisive factor in the Owls’ upset of fourth-seeded Tennessee was the guy on the other bench.

Rick Barnes crashed out of yet another NCAA men’s tournament on Thursday night. For those keeping track, he has yet to get out of the Sweet 16 in eight seasons at Tennessee. It's been 15 years since he made an Elite Eight, back when he was still at Texas.

In 36 seasons as a head coach, often of teams loaded with enough talent to make deep runs, Barnes has one Final Four and two Elite Eights on his resume.

“Don’t ever, ever, ever take for granted how hard it is to get here to start with, and then how hard it is to win a game and then another game,” Barnes said after the 62-55 loss. “It’s really, really hard.”

Yes, but this is why Tennessee has made Barnes the fourth-highest paid coach in the country, earning $5.45 million a year. To win games like this.

There is no question Barnes is an exceptional coach. He’s only had three losing seasons in his career, and his teams are almost always in the Top 25 or hovering at the edge of it. He has them in the mix for conference titles, regular season and tournament.

But sometime around, oh, March 10, it all implodes. This isn’t just the wheels falling off. This is the radiator blowing, the exhaust pipe leaking, the headlights burning out and the engine catching fire. At some point, it stops being about bad matchups and untimely injuries and becomes about Barnes not being able to cut it come NCAA tournament time.

Take this game.

It was only five days ago the Volunteers dismantled a late-surging Duke team that many thought had a shot at the Final Four. Tennessee had seemed to figure out how to make do without point guard Zakai Zeigler, who tore his ACL on March 1 against Arkansas, and the early ousters of top-seeded Purdue and No. 2 Marquette opened what should have been a wide path to the Final Four.

Instead, the Vols are done, knocked out by a ninth-seeded team that had made one other trip to the tournament 21 years ago and exited without winning a game.

Yes, parity has made upsets like this more possible than ever, and the Owls were fearless. But this was a game the Vols lost as much as FAU won.

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A game Barnes lost.

When FAU was in the midst of its 18-2 run in the second half, Barnes was paralyzed on the sideline. For 5½ excruciating minutes, as the Owls took what had been a six-point deficit and turned it into a seven-point cushion, Barnes did nothing. He didn’t call a timeout, he didn’t give his players time to regroup.

He just let it unravel.

“They got some separation, they got relaxed,” Barnes said.

Finally, after FAU had scored 15 of those 18 points during the run, Barnes called a timeout. But whatever he schemed up didn’t work. After the break, Florida Atlantic took the next three field-goal attempts, making one of them.

When Jonas Aidoo finally broke the fever with a putback, the damage was done.

The Vols played cautiously and without any of the aggression or confidence they should have had. This is a team that knocked off then-No. 1 Alabama, then-No. 2 Gonzaga and then-No. 3 Kansas during the regular season, and was somehow completely befuddled by FAU.

An opponent for which it had five days to prepare.

“We had some breakdowns with certain players today that we just felt like they weren't locked in as much as they needed to be,” Barnes said. “You'd expect them to be, but it's a big stage.”

That’s what their coach is for, to pull them back together when things are going south. Better yet, have them mentally prepared before they even take the floor.

The loss of Zeigler was a factor, of course. But that’s on Barnes, too. He didn’t have another true point guard on the roster, which meant there was no one to take over as floor general when Zeigler got hurt. You know, somebody who could have slowed the game down, provided a steadying presence as the Vols’ season was going up in flames.

Coaches often get too much of the credit when things go right and too much of the blame when they don’t, but this is the time of year when it really does make a difference.

There’s a reason “Izzoed” becomes a verb in March. Gonzaga doesn’t storm back from 13 points down to beat UCLA on Thursday night if Mark Few isn’t on that bench. Odds are Kansas would still be playing had Bill Self been at the game last weekend.

They have earned their legacies in the postseason. Just as Barnes has earned his.

“When it ends like this,” he said, “it’s always disappointing because we want (to win) it all and (we) came up short.”

That's what Barnes does in March.

Follow USA TODAY Sports columnist Nancy Armour on Twitter @nrarmour. 

This article originally appeared on USA TODAY: Rick Barnes not the coach you want on the bench come tournament time