Alfred Morris blasted the Redskins for 127 rushing yards Thursday. (Jonathan Newton/The Washington Post)

ARLINGTON, Tex. — The Dallas Cowboys couldn’t throw the ball. Dak Prescott continued his month-long struggles and, coupled with a hand injury he suffered during the game, Dallas was forced to become one-dimensional on offense.

The task was simple for the Redskins defense: Stop the run. It’s often the primary goal for this team, forcing offenses into third-and-long passing situations so it can allow its pass rushers to get after the quarterback. Yet Washington couldn’t accomplish its goal Thursday night.

The beneficiary was none other than former Redskins player Alfred Morris, who has filled in as the starting running back during Ezekiel Elliott’s six-game suspension. The Redskins weren’t able to stop the Cowboys’ ground game during the second half of their 38-14 blowout loss Thursday night at AT&T Stadium.

Washington’s defense couldn’t sustain its first-half success, when it conceded just 103 yards despite a 17-7 deficit at halftime, in part because of the physicality the Cowboys showed running the football. Morris finished with 27 carries for 127 yards and a touchdown, with 89 of those yards in the second half.

“We missed a few tackles here and there, and they were able to wear our defense down a little bit,” Redskins Coach Jay Gruden said. “They have a big offensive line, physical offensive line. [Jason] Witten’s as good a blocking tight end as there is in NFL history. They wore us down a little bit, and Alfred ran hard.”

Morris averaged nearly six yards per carry in the second half, dictating the pace of the game on 15 carries over the final 30 minutes as Prescott finished with just 102 passing yards. As he displayed during his four seasons with the Redskins, Morris improved as the game progressed while wearing the defense down.

“That was probably a little bit of his attack mentality, where he was more motivated playing against the Redskins,” Prescott said.

The Cowboys had two second-half scoring drives that lasted more than five minutes. One began near the end of the third quarter and continued at the start of the fourth on an 11-play, 84-yard drive that lasted 5:28. Morris gained 29 yards on five carries on the possession, which ended on Prescott’s 13-yard touchdown pass to receiver Dez Bryant.

“They were just running the ball,” Redskins linebacker Zach Brown said. “They get in heavy formations and just run the ball. They brought three tight ends and one receiver. We should’ve went like a heavy package or something, take one of the corners out, because they’ve got three tight ends in the game. They’re going to run the ball.”

On the Cowboys’ next possession, Morris capped a 10-play, 75-yard drive that spanned 6:33 with his only touchdown, from one yard out. Morris gained 44 yards on seven carries; Washington had no answer as Dallas handed Morris the ball on the first four plays of the series for positive yards.

“[Morris] cuts, but he takes like five to eight steps to [expletive] cut,” Brown said. “He’s a one-cut back. He can’t cut at all. It’s just his O-line gets on the second level. They do a good job of getting to the [linebackers]. So I got to give credit to their O-line today. They did a good job.”

It was the first time Morris eclipsed 100 rushing yards in his two seasons with the Cowboys. He hadn’t reached that mark since his final regular season game with the Redskins – Week 17 against the Cowboys in 2015 at AT&T Stadium.

“Alfred was outstanding,” Cowboys Coach Jason Garrett said. “He’s got a great feel and instinct for running the football. He makes a lot of runs that people don’t really recognize how good they are. Little subtle runs – four-, five-, six-yard runs – where he’s finding the crease, finding the soft spot and moving forward. And he was able to do that throughout the ballgame. He’s a damn good football player.”

Before Thursday, Morris averaged just 60 rushing yards in the Cowboys’ three games without Elliott, but he gained nearly five yards per carry against the Redskins. His 27 carries were the most since his rookie season, when Morris compiled 1,613 rushing yards for Washington. The heavy workload paid off for the Cowboys — and ruined any shot of a comeback for the Redskins.

“I didn’t do anything special,” Morris said. “You can give the credit to the O-line. You can give the credit to the play calling. You can give the credit to just a good run scheme. …

“I’m just super thankful for this opportunity. I’m super thankful for us to turn this thing around. I mean, it’s only one game. We still have a lot more games to play to do what we want to do: get into the postseason. So we’ll see what happens, but this is a good win.”

More on Thursday night’s game:

Redskins’ playoff hopes effectively dashed with 38-14 loss at Dallas

Brewer: Coming in, the Cowboys were the team playing ugly. That didn’t last Thursday night.

Redskins WR Jamison Crowder was pivotal, but for all the wrong reasons

The best and worst moments from Thursday night’s loss