Even through the facemask of his helmet, Zack Moss’ smile left a lasting impression.

In the third quarter last Saturday in the LA Coliseum, the Utah running back caught a swing pass at the Ute 47, turned upfield, ran through a half-hearted tackle attempt by a defensive back, and delivered a teeth-rattling forearm shiver to USC’s All-Pac-12 inside linebacker Cameron Smith. A 6-foot-2, 250-pound junior, Smith went crashing to the turf as Moss went on to pick up another 10 yards.

With television cameras fixed on Moss as he turned to line up for the next play, a smile stretched from one ear to the other. Moss, a 5-foot-10, 210-pound sophomore wasn’t the only one who enjoyed his 141-yard rushing performance (he also pulled in three catches for another 26 yards) in the Utes’ 28-27 loss to the Trojans. The attitude he brought to the game excited Utah coach Kyle Whittingham as much as anything he saw on the field that night.

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“I can’t tell you exactly what the mindset was, but I can tell you that he looked exactly how we wanted him to look when we recruited him,” Whittingham said. “He was running over people, exploding into would-be tacklers. He made so many explosive, violent runs in that game and it was impressive.”

The Utes came into the season with plenty of valid questions about their ability to sustain a running game having lost four starting offensive linemen as well as running back Joe Williams, who rushed for 1,438 yards despite playing in just nine games due to his short-lived retirement, to the NFL.

Even in the first third of this year’s schedule, the most dynamic aspect of the Utah running attack appeared to be quarterback Tyler Huntley. Whether Huntley’s injury forced the rest of the offense to pick up its play or the offensive line has simply benefited from more time together, the Ute rushing game has shown signs of progress since the start of Pac-12 play.

Moss said earlier in the season he’d been “too patient” and looking for a big play every carry. In the past three games, he’s felt like he’s been running harder and more decisively picking and hitting the holes.

“Going back to high school, I always looked for the big play,” Moss said. “Now, I understand that the big play is going to come. You can’t rush that type of stuff. I got back to just taking it play-by-play and making the best of that play, and if the big play comes it’s special, it just comes.”

Moss’ 141 rushing yards against USC marked his first 100-yard game since he sliced through FCS opponent North Dakota in the season opener. Moss won the starting running back job in preseason, but he’d been battling back and forth with Armand Shyne before Shyne suffered a season-ending arm injury late in camp.

(Chris Detrick | The Salt Lake Tribune) Utah Utes running back Zack Moss (2) runs past North Dakota Fighting Hawks defensive back Torrey Hunt (16) during the game at Rice-Eccles Stadium Thursday, August 31, 2017. Utah Utes are leading North Dakota Fighting Hawks 17-9 at halftime.

“Undoubtedly I think he can be the featured back in this system,” Pac-12 Network analyst Yogi Roth said. “He showcased the burst, he showcased the ability to lower his shoulder, the physicality. In pass-[protection], he stuck his head in there.”

Moss has been quick to point to the improved running room created by the offensive line. The Utes’ offense has averaged better than 4 yards per carry in each of the past two games.

“They’ve been making bigger holes than earlier in the year,” Moss said. “Earlier in the year, they were real small. They’ve been getting a lot better push. They’ve been taking [the challenge] on themselves. They’ve been hearing things, so they’ve been doing a good job of that.”

Senior co-captain Salesi Uhatafe entered this season as the line’s lone returning starter, and he shifted from right guard to left guard. The other four starters — left tackle Jackson Barton, center Lo Falemaka, right guard Jordan Agasiva and right tackle Darrin Paulo — were all making a jump to full-time starting jobs. Agasiva, a highly-regarded JUCO recruit, hadn’t played one snap of Div. I football before the season opener.

That group has enjoyed continuity this season with the same five starters having been together for all six games. Utah assistant head coach and offensive line coach Jim Harding was impressed with Moss on Saturday, running downhill, staying in bounds and finishing runs going forward.

“I think they’ll continue to get better as the weeks go on,” Harding said of the line. “With four new guys, it takes times to get used to one another. I think we did take a step forward, but there’s plenty of things we still need to work on to get better each week.”

Christopher Kamrani contributed to this report.

UTES GROUND GAME

Team rushing

Aug. 31, North Dakota: 272 yards, 47 rushes, 5.8 per carry

Sept. 9, at BYU: 116 yards, 36 rushes, 3.2 per carry

Sept. 16, SJSU 160 yards, 40 rushes, 4.0 per carry

Sept. 22, at Arizona: 112 yards, 38 rushes, 2.9 per carry

Oct. 7, Stanford: 144 yards, 33 rushes, 4.4 per carry

Oct. 14, at USC: 169 yards, 41 rushes, 4.1 per carry

Moss rushing

Aug. 31, North Dakota: 128 yards, 22 rushes, 5.8 per carry

Sept. 9, at BYU: 21 yards, 11 rushes, 1.9 per carry

Sept. 16, SJSU: 43 yards, 11 rushes, 3.9 per carry

Sept. 22, at Arizona: 73 yards, 14 rushes, 5.2 per carry

Oct. 7, Stanford: 79 yards, 15 rushes, 5.3 per carry

Oct. 14, at USC: 141 yards, 20 rushes, 7.1 per carry