Win or lose, the one constant with Marcus Mariota in postgame press conferences as a pro has been an even-keeled disposition.

He naturally smiles more in victory and may be a bit — just a bit — more expansive in his comments. But whatever the outcome of the game, the words are carefully measured and body language tempered, giving little insight to the depth of the triumph or torment in his soul at the moment.

Which is why his appearance after the Tennessee Titans’ 12-7 loss at Arizona on Sunday was so noteworthy and revealing.

It was the first time in his three seasons in the NFL we’ve seen — and, indeed, heard — him “pissed off,” as he almost barked it.

“Frustration is an understatement,” a smoldering Mariota told the assembled media, which should tell you a lot.

There was a lot to be upset about on a day the Titans’ offense vegetated and a sprained left knee suffered in the first half was not the extent of his pain for the day.

Mariota, as is his character, placed himself directly under both axles of the bus for a misfiring offense that included two interceptions, 16-for-31 passing for 159 yards and a quarterback rating of 39.6.

The next finger he publicly points at a teammate or coach or anyone else but himself will likely be his first.

“The defense played lights out, special teams did their job and I have been hurting our team and I have to find ways to get better and improve,” Mariota said. “I expect myself to do my job, and that’s taking care of the football and converting third downs. I haven’t been up to par. I have to be better.”

To be sure, he has airmailed some balls and made questionable decisions on others. But you sensed that what agitated him went beyond the widening disparity between his touchdowns (10) and interceptions (14) and growing sack count (17) this season.

An inconsistent, often-disappearing running game, receivers who went off pattern — again — a lack of protection and unimaginative play calling no doubt contributed to what was roiling Mariota, even if he wouldn’t put it into so many words before the microphones and cameras.

Receiver Rishard Matthews later shouldered the blame for one of the interceptions, acknowledging he went outside instead of in on the route — just as in the four-interception 40-17 loss to Pittsburgh last month, where rookie receiver Corey Davis a day later acknowledged, “Two of those picks he threw were my fault.”

A few weeks ago, when Mariota and the Titans were pulling off fourth-quarter comebacks to assume a share of the AFC South divisional lead, the road to the playoffs looked clear.

Now, at 8-5, the Titans need to rediscover their mojo — and pronto.

That means putting their franchise quarterback in a position to perform like one and not feeling like he has to make everything happen.

It means taking advantage of his gifts as a dual-threat performer (when they can keep him healthy) and not confining him to a drop-back passing mode and predictable passing situations.

This is supposed to be the year that the Titans make their move to the postseason for the first time since 2008. But after a promising start, including a four-game winning streak, they have curiously shown repeated signs of regression.

Now we wait to see if the competitive fires that burned within Mariota can relight the Titans.

Reach Ferd Lewis at flewis@staradvertiser.com or 529-4820.