For the first time since 1998, when Jason Garrett was playing quarterback for the team, the Dallas Cowboys had two running backs finish a game with more than 100 yards each on the ground.

Ezekiel Elliott on Sunday finished with 125 yards and a 68.4% success rate on 19 carries (6.6 yards per) while Tony Pollard accumulated 103 yards, a touchdown and a 69.2% success rate (NFL average is 47%, according to Sharp Football Stats) on 13 carries (7.9 yards per) as the Cowboys sliced and diced Miami's defense.

While we've come to expect this kind of performance from the two-time NFL rushing champion, especially against overmatched opponents, Sunday provided a glimpse at how the Cowboys' two-headed monster in the backfield can operate in the future.

Elliott is the bell cow who gets the lion's share of opportunities and pounds defenses into submission. He can attack them between the tackles and on the edges with equal potency, blending speed, elusiveness and power as well as any back in the league. Elliott is also very comfortable in pass protection and an effective receiving option out of the backfield, especially on screens.

Pollard, on the other hand, is still in the infancy stages of his career, so he is more of a mystery. Coming out of Memphis, Pollard was billed to be more of an running back/wide receiver hybrid who was just a bigger version of former Cowboys running back Lance Dunbar.

His performance against the Dolphins revealed that he is actually much more.

Pollard is the rare kind of back who is both an ideal backup to have in case the starter gets hurt and a perfect complement to the starter's skill set, as teams are typically forced to employ different players for each of those roles.

For Pollard to be an effective backup to Elliott, he has to be successful in a traditional running back role, meaning he has to be productive between the tackles. Pollard didn't do a ton of running between the tackles at Memphis, but he's looked extremely comfortable in that aspect since arriving in Dallas.

His 16-yard touchdown run against Miami was a great example:

On this play, the Cowboys run wide zone left using 21 personnel (two running backs, one tight end, two receivers).

Once Pollard receives the ball, he does a good job of quickly reading his blocks. With Dalton Schultz's inside leverage against the edge defender, Pollard understands he can't bounce the ball outside, so he has to execute a bang read behind his fullback's block or bend his path backside. With Connor Williams successfully reaching the play-side defensive tackle, Tyron Smith engulfing a play-side linebacker at the second level and Jamize Olawale picking up the final linebacker, Pollard makes the correct decision to bang the run into the C-gap.

Olawale, however, fails to secure his block as Miami's Sam Eguavoen (No. 49) blows the Cowboys fullback up, putting himself in Pollard's immediate path.

Pay attention to Pollard's footwork as he meets the linebacker in the hole. A subtle jab step inside before dropping his pads and accelerating outside causes Eguavoen to shift his weight inside ever so slightly, preventing him from tackling Pollard squarely. This, combined with Pollard's low center of gravity, enables the Cowboys rookie to power through an arm tackle before outrunning two defensive backs to the end zone.

Pollard is an effective complement to Elliott because he is a big-play threat every time he touches the ball. Given that Elliott is viewed as a top-three running back in the NFL, defenses naturally shift their focus from the run to the pass. This is evidenced by the fact that Pollard has seen eight-plus defenders in the box on just one of his 30 carries (3.33%), according to NFL's Next Gen Stats.

He took advantage of light boxes Sunday and turned them into a couple of big plays -- the longest of which was a sublime, 28-yard run in the fourth quarter:

On this play, the Cowboys run a split-zone concept using 12 personnel (one running back, two tight ends, two receivers) against Miami's base defense.

Once the ball is snapped and Pollard receives the carry, he reads Blake Jarwin kicking out the initially unblocked edge defender while Smith and Williams cave the three-technique defensive tackle in, which informs him to press the hole and cut backside into the empty void.

Even though the backside alley is open from the moment he receives the ball, Pollard expertly stays patient and presses the line of scrimmage before cutting. Look at what that does to linebacker Jerome Baker (No. 55). Instead of flowing over the top of the three-tech to fill the void, Pollard's initial downhill path forces Baker to stay inside, keeping the backside void free of defenders.

Once Pollard cuts backside, he identifies Xavien Howard (No. 25) mirroring Dallas' jet motion to the near sideline. With Howard's momentum taking him outside of the hash marks, Pollard quickly plants his outside foot into the ground and accelerates underneath the cornerback -- nearly breaking his ankles in the process -- to get into open space.

From there, Pollard eludes one more defender before being dragged down from behind by others.

Pollard's contact balance, elusiveness and burst enable to him to maximize the well-blocked touches he does receive. Against Miami, Pollard averaged 5.54 yards after contact per carry -- best in the NFL among running backs with at least two carries in Week 3, according to Pro Football Focus. He benefited from some great blocking at times, but he also did his part to create more than what's blocked for him.

Pollard doesn't need perfect blocking to be successful. Here's a great example:

On this play, the Cowboys run a wide-zone concept using 13 personnel (one running back, three tight ends, one receiver) against Miami's base defense.

When the ball is snapped, a miscommunication up front between Williams and Travis Frederick gives nose tackle Davon Godchaux free access to the backfield. Because of the penetration, Pollard is forced to bounce the ball outside despite there being an alley in the C-gap -- where he would have run if not for penetration -- between Schultz's kick-out block on the edge defender and La'el Collins' climb to the second level.

Luckily for Dallas, Pollard's burst allows him to beat Godchaux to the edge before cutting upfield for a nice 6-yard gain to put the offense in a second-and-short situation.

While this play may look ordinary to Cowboys fans who've been spoiled with running back talent since DeMarco Murray was drafted in 2011, it's actually an impressive feat to elude penetration and secure a successful run that keeps the offense ahead of the sticks.

Though much has been said about Pollard's ability when Elliott is off the field, his rare skill set affords Kellen Moore and the offensive coaching staff the ability to get creative by putting both of them on the field at the same time.

Moore has been slow with his deployment of this package to start the season, but he provided a glimpse at what Dallas can do with Elliott and Pollard in the game together. Here's a great example:

On this play, the Cowboys are in 20 personnel (two running backs, no tight ends, three receivers) with Elliott and Pollard initially in the backfield.

Right before the ball is snapped, Pollard is motioned to the flats, setting up a bubble screen with two receivers blocking in front of him. Prescott's pass is slightly off target, forcing Pollard to slow his momentum. This throws the timing of the bubble screen off, but Pollard navigates around his blockers, using a nifty jump cut off of Randall Cobb's block, to pick up the first down before the pursuing defenders can drag him to the ground.

While this play may look like a simple bubble screen to a back motioning out of the backfield, it's actually a run-pass option (RPO) that has an inside zone (run) tagged with a bubble screen (pass). This means, depending on the defense's look, either Elliott or Pollard can get the ball on this play -- a truly scary proposition for defenses.

In the above play, the defense's confusion up front -- look at the late rotation by Eguavoen (No. 49) -- allows Dallas to outleverage Miami with the bubble screen, as Pollard's short jet motion gives the Cowboys a 3-on-2 advantage outside the hash marks.

If the Cowboys hit this cleanly (meaning Pollard catches the ball in stride), there's a decent chance it turns into a touchdown or at least an explosive play (15-plus yards), given the open space and lack of defenders downfield.

What's more exciting about this particular play is that it just scratches the surface of what Dallas can do with Elliott and Pollard in the game. Given Pollard's skills as a receiver -- out of the backfield and from traditional receiver alignments -- there are seemingly endless opportunities to create mismatches and big-play chances with both backs in the game.

The Cowboys can continue to use RPOs where Elliott is the run option and Pollard is the pass option, or vice versa. They can also align Pollard detached from the formation and use him for jet sweeps with Elliott in the backfield. If the Cowboys want to get really creative, they can use the threat of Prescott's legs on triple-option concepts, similar to how the Carolina Panthers used them in the past. And those are just a few of the myriad of options (no pun intended) Moore could integrate into the offense with Elliott and Pollard on the field.

Pollard's stellar performance Sunday not only showed why he's the perfect backup and complement to Elliott, it also provided a glance at the potential of using both running backs at the same time.

Enjoy this post? More film studies:

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Twitter: @JohnOwning