DeMarco Murray delivers in a hurry

ARLINGTON, Texas -- DeMarco Murray stood behind a lectern wearing a two-button gray blazer. He looked like a young professor about to teach class to a bunch of old guys who thought they'd seen it all and knew it all.

Murray, the Dallas Cowboys' third-round draft pick out of Oklahoma, showed everybody something on Sunday afternoon and gave a lesson on how to be an every-down running back.

He ran hard, he ran fast, and he ran well. When he was tired, he protected the ball and fell down. You could also say he ran smart.

He ran all the way to a franchise-record with 253 yards on 25 carries in the Cowboys' 34-7 victory over the St. Louis Rams. It was the 10th-best rushing day in NFL history.

Murray also had the second-longest touchdown run in franchise history, 91 yards, and of course set the Cowboys' rookie record.

"I never thought in a million years I would have this kind of day," Murray said.

If the Cowboys know what's good for them, Murray will get his first NFL start next week at Philadelphia.

That's right, Murray didn't start against the Rams. That honor went to Tashard Choice, who gained 8 yards and lost a fumble on two carries starting in place of the injured Felix Jones.

The starting job should belong to Murray until Jones' ankle is healed.

"I'm just going to take it one day at a time," Murray said. "Felix is our starter and he's a great leader in the running back room.

"When you get an opportunity you got to continue to work hard, and I'm ready to be the No. 1 guy, No. 2 guy, No. 3 guy. Whatever they ask me to do, I'm going to do that."

What Murray did Sunday against one of the NFL's worst run defenses was move into Emmitt Smith and Tony Dorsett's class.

For one day.

Smith, a Hall of Famer and the NFL's all-time leading rusher, held the team's single-game record of 237 yards since 1993. Dorsett, another Hall of Famer, owned the rookie mark of 206 yards since 1977.

When the Cowboys realized Murray was nearing Smith's record in the fourth quarter, they gave him more carries instead of giving extra work to rookie Philip Tanner.

A few plays after getting the record, Murray walked off the field like a pitcher who had just shut down an opponent for seven innings and was greeted by receiver Dez Bryant.

Running backs coach Skip Peete was there, too, and other players greeted him. It was one of those days.

"It's unbelievable," Murray said.

Bryant said he wasn't as surprised at Murray's effort as the rest of us might be.

"It came out of nowhere to ya'll," Bryant said. "You don't see the way he prepares for the game."

So the Cowboys must be ready to give Murray the bulk of the carries next week, right?

"We just have to see what the health of Felix Jones is," coach Jason Garrett said. "We're certainly hopeful we get Felix back. He's been our bell-cow runner here for the last year or so. He's done an outstanding job with his opportunities so far, but certainly DeMarco warrants some playing time after today's performance."

That's coach-speak, but after seeing Murray burst through the line, juke past defenders, run through arm tackles and hit the holes hard, you have to believe Murray will take over.

Perhaps as impressive as Murray's elusiveness was his decision making. On a 43-yard fourth-quarter run with the Cowboys leading 20-7, he just stopped and fell down to end it at the Rams 30.

"I was just a little gassed," Murray said. "I was just trying to be smart and get down and not do anything extra and possibly fumble the ball."

What a concept.

Things change week-to-week in the NFL when it comes to running backs. When the Cowboys get to Philly next week, Murray might get shut down. If that happens, what will we make of him then?

Sunday afternoon, however, was more about celebrating what Murray had achieved. While the NFL is all about the big picture, in singular fashion it was nice to see a great performance.

"Any time you have 250, I don't care who had it before you, it's pretty serious," wide receiver Miles Austin said. "More power to him. Hopefully he can keep it going."

Calvin Watkins covers the Cowboys for ESPNDallas.com.