ARLINGTON -- Even at 73, it wouldn't have been surprising to see owner Jerry Jones skipping to the locker room Friday night after the Cowboys' preseason win over Miami.

It's been that kind of week for him.

He was named a Pro Football Hall of Fame finalist on Tuesday. Three days later, he watched rookie Dak Prescott turn in a perfect quarterback rating in shredding the Dolphins' defense.

Jones and club officials are downright giddy behind closed doors about what they've seen so far from Prescott. Publicly, they're doing all they can to maintain poker faces, saying they won't rush to name Prescott the backup quarterback and dismiss any possibility of adding a veteran as teams make their final cuts Sept. 3.

With two more preseason games left, there's really no need for Jones to make any declaration regarding the roster.

But for all practical purposes, the race for the Cowboys' backup quarterback spot appears to be over. And Prescott has lapped the field.

If the Cowboys had really wanted, they could have signed Matt Moore -- who was the second quarterback in the game Friday for the Dolphins -- in the offseason. If they had really wanted, they could have signed Nick Foles a few weeks ago after backup Kellen Moore was lost for three to four months with a fractured right ankle.

But Prescott has played so well -- and has been equally impressive in the classroom -- that the Cowboys haven't been forced to add a quarterback with experience.

"There's an old adage that if you've seen it and you've seen it pretty good, well then you know it's there, you know they can do it," Jones said after the win over Miami. "The question of many college quarterbacks is can they operate in the pro game, in the pro system. We've seen him do it at practice. We've seen him do it in meeting sessions. We've seen him carry that now to games.

"There is an energy that comes with him to the field. That same energy, surprisingly, comes with him to the classroom. That same energy comes with him in many different ways. You got to add that up, but on the other hand, let's don't get ahead of ourselves here. That would be a mistake. Of course we don't have to. We are in a situation where we can have a developing but adequate -- because of the excellence of Tony Romo -- we can have that behind him. To me that's what you're ideally striving for."

Prescott has been much more than adequate through the first two preseason games. He has more touchdowns (six) than incomplete passes (five).

He's played essentially one full game. In 66 snaps, he's 22-for-27 passing (two were drops) for 338 yards, four touchdowns and no interceptions. He also added two rushing touchdowns against Miami.

"The more reps I get," Prescott said, "the better I feel I'm going to be."

The former Mississippi State standout showed the Cowboys everything they would need to see against Miami.

He rolled right and completed passes to Geoff Swaim and Alfred Morris on the run. He rolled left and completed a pass to receiver Lucky Whitehead on the run. He delivered a perfect touch pass to Dez Bryant for a touchdown. Prescott showed his athleticism on a 20-yard touchdown run in the second quarter on third-and-10.

The fourth-round pick capped off his highlight reel with a pass that traveled 61 yards in the air for a 58-yard completion in the third quarter to receiver Brice Butler that set up first-and-goal. On the ensuing play, he threw a perfect back-shoulder pass to Butler for the touchdown.

Not bad for the eighth quarterback selected in this year's draft.

Keep this in mind, too: The Cowboys will pay Prescott only $2.45 million over the next four seasons.

Cowboys quarterbacks coach Wade Wilson said after the first preseason game against the Rams he went to each of the Cowboys' starting offensive linemen and asked them how Prescott was in the huddle. To a man, they said he was poised and polished.

Wilson raves about how good of a note-taker Prescott is as well, never afraid to ask a question.

During the Cowboys' three weeks of training camp in Oxnard, Calif., Prescott was often the first one on the practice field each evening and the last one to leave.

"Anytime you see a rookie come in and have the production he has had that is surprising for any rookie," Cowboys executive vice president Stephen Jones said after the win over Miami. "But in terms of from the day he walked in the door he has shown a lot of unique intangibles, rare intangibles in terms of his leadership, his people skills, his ability to lead. He wants to learn. He wants to work hard.

"He will continue to do that and not take anything for granted."

Twitter: @DMN_George