"I felt comfortable out there being able to articulate everything that the coaches wanted," Mariota said. "... I threw it all right. I missed a couple throws here and there but for the most part I thought it was OK."
Coach Ken Whisenhunt said the defense is a bit ahead of the offense,as is typical at the start.
"I guess the best assessment would be some good, some bad," he said. "Probably what you expect."
The coach mentioned one 30-yard scramble up the middle on a broken play as a highlight.
Mariota said he threw an interception and lost a fumble, rating the ball protection that was a hallmark for him at Oregon as "not so good." But he often threw the ball as well as any of the other quarterbacks on the field, including second-year man Zach Mettenberger and Charlie Whitehurst.
Mettenberger spoke publicly for the first time since the Titans used the No. 2 pick in the NFL draft on Mariota last month. He'd previously told ESPN's Adam Caplan that he would "fight to the death" to keep the starting job.
"I was just trying to be funny and of course through text message you can't really see the sarcasm and me trying to be funny in that," he said before turning up the sarcasm meter again. "But I am, I would fight him to the death right now. Give me an ax, give him maybe a mace or something, we'll do it."
"He's been great, he's really got a sharp personality," Mettenberger added. "He doesn't need a lot of my help, he's been picking up things very quickly, but if he asks we'll all definitely help him out."
Mariota said he enjoyed some trash talking that was aimed at him by the defense.
"It makes it enjoyable," he said. "Every day you're fighting for bragging rights in the locker room. When it's highly competitive like that, everybody kind of continues to make your team better."
Players were certainly curious about the new starter and how his quiet demeanor translated when he got on the field.
"When he gets in the huddle, he calls the play with confidence, everybody is ready to roll," said Kendall Wright, who also complimented Mettenberger.
Hakeem Nicks, a veteran wide receiver who is also a newcomer, said Mariota reminds him some of Eli Manning because of their similar soft-spoken demeanors.
The Titans have a second OTA practice Wednesday. Mariota, second-round receiver Dorial Green-Beckham and fifth-round running back David Cobb will miss Thursday's practice for the NFL's rookie premiere.
Mariota practices with Titans' veterans
ESPN Titans reporter Paul Kuharsky breaks down rookie quarterback Marcus Mariota's performance in his first practice with the Titans' veteran players.