In Wynne, Ark., DeAngelo alternated playing time with guys named Antonio and Demontate.

In Lacey, Wash., Jonathan split carries with Terrence.

"I've always been mixed in [as] a tandem," Stewart said. "It makes sense to have two good running backs because you're always pounding the rock, and it's good to have fresh legs in there just about every time you run the ball."

As they sat together after practice, meetings and working out, they were asked how they avoid jealousy, back-biting and other potential pitfalls that could infect their relationship if either of them became too me-first.

"Well, I look at it like I've never been that type of dude in the first place since I started playing Football," said Stewart, a rookie.

"What type of dude is that?" said Williams, interrupting Stewart and assuming the role of conversation emcee.

"Humble," Stewart said.

"You've never been the type of dude to be humble?" Williams asked.

Stewart told Williams to stop trying to confuse him, and they laughed.

Their relationship, fullback Brad Hoover said, is a classic case of opposites attracting.

"DeAngelo is real outgoing and outspoken," Hoover said. "Jonathan is real laid-back and kind of reserved.

"It's [good] how close they are and how everything has worked out. It could've been a dicey situation for us with those two this year."

Williams, a third-year pro, and Stewart are centerpieces of an 8-2 Panthers team that plays at 6-4 Atlanta today in a key NFC South game.

The matchups pits the NFL's No. 2 rushing attack (Atlanta) vs. the No. 6 (Carolina).

The Falcons feature the league's third-leading rusher, Michael Turner (971 yards) and a talented reserve, Jerious Norwood (383 yards).

The Panthers have more of a balanced attack, with Williams and Stewart serving as options 1a and 1b. Williams has more rushing yards (782-513) and carries (153-118) than Stewart, but they've split playing time more evenly than all but a handful of NFL running back combinations.

The Panthers are the only team in the league with two backs who each have at least 100 carries, 500 yards rushing and six touchdowns.

Last week against Detroit, Williams and Stewart became the first backfield pair in team history to rush for 100 yards each in the same game.

Getting acquainted

Both backs were college All-Americans -- Williams at Memphis, Stewart at Oregon -- who became first-round draft picks.

Williams arrived at Carolina in 2006 and shared playing time with DeShaun Foster for two seasons.

When Foster was released in February, the Panthers targeted a running back in the draft and took Stewart with the 13th overall selection, 14 spots higher than they had selected Williams two years earlier.

"When they brought Stew in, I was excited because I was going to be the guy who was going to not necessarily mentor him, but kind of show him the ropes," Williams said. "I relished [it]. I was really looking forward to doing it."

Stewart said he came to the Panthers "wondering what De-Angelo was going to be like."

"He turned out to be real cool," Stewart said.

The Williams-Stewart partnership advances a plan coach John Fox began implementing in 2003 when Stephen Davis and Foster shared the running back responsibilities for the Panthers' lone Super Bowl team.

Davis was the clear lead runner that year (318 carries for 1,444) yards, and Foster was the backup (113 rushes for 429 yards).

Fox said he prefers having two quality backs because the position "is so expensive on the body."

"You need a [second] guy because they're going to get nicked," Fox said. "You've got 11 guys [on defense] trying to take their heads off on every play."

Panthers quarterback Jake Delhomme said when Williams and Stewart are older, they'll be glad they had the other to limit their punishment in these early years of their careers.

Linebacker Jon Beason said the two-back philosophy gives the Panthers an advantage against opposing defenses. He likened Williams and Stewart to playing Minnesota earlier this season when Vikings' backs Adrian Peterson and Chester Taylor alternated on some long drives.

"You're sucking air and they come in fresh and run the ball," Beason said. "It almost makes you mad when they put in a fresh back because it's like, 'It's not fair. He's taking a rest.' "

Some of the NFL's most successful teams this season are using multiple running backs extensively. The 9-1 Giants have a three-man attack with Brandon Jacobs, Derrick Ward and Ahmad Bradshaw. The 10-0 Tennessee Titans have rookie Chris Johnson of East Carolina teaming with LenDale White.

Williams the sage

The friendship Williams and Stewart share extends off the field and into the virtual world of "Xbox Live."

They wouldn't divulge how much time they spend on the hobby, but agreed it's plenty.

Stewart was about to name their favorite "Xbox" game, but Williams wouldn't let him.

"We don't want to hype a game they're not paying us to hype," Williams said.

Stewart has become accustomed to receiving such sage advice from Williams, who jokes that Stewart still has lots to learn about being a pro.

Stewart, for instance, wasn't sure what to call the Panthers' spring minicamp other than "practice" and referred to the team's talent scouts as "recruiters," a term more commonly used in college.

"See, he doesn't know the name of things yet," Williams said.

But, in a serious moment, Williams said Stewart helps him, too.

"What a lot of people don't understand is when I'm in or he's in the game, we're constantly talking on the sidelines when we're coming [in and] out," Williams said. "He may see a hole I don't see, or vice versa. It helps us out having an extra set of eyes."

Williams said Stewart tells him runs he shouldn't make because he'd get "banged" by the defense.

And Stewart said Williams yells from the sidelines to alert him the defense is converging.

"I'm sure he can pick my voice out of a crowd," Williams said, "and I can pick his out of a crowd."

They say they don't have a nickname yet, but concede that "Smash & Dash" seems to be most popular with Carolina fans.

If that sticks, Stewart will be "Smash" because he's has a more physical running style. But Williams said Stewart has plenty of "Dash" in his step, too.

As they grabbed their packpacks to leave a Bank of America Stadium meeting room at the end of a long day, Williams said, "It's about time to take this dog and pony show on the road."

"He's the dog," said Williams, pointing to Stewart, "and I'm the pony."