Smallwood rushed for 163 yards and a touchdown, Shell had 111 yards and two scores, and West Virginia beat Texas Tech 31-26 on Saturday.
West Virginia (4-4, 1-4 Big 12) broke a four-game losing streak while Texas Tech (5-5, 2-5) lost its third straight in trying to become bowl eligible.
"It's been a long month and a half," West Virginia coach Dana Holgorsen said. "Just to get that victory is obviously pretty good."
The Mountaineers compiled 300 yards on the ground against one of the nation's worst rush defenses. Shell and Smallwood surpassed 100 yards against the Red Raiders for the second straight year.
Shell, who had averaged 33 rushing yards in his three previous games, earned his first 100-yard effort of the season.
During the week leading up to the game, Shell said running backs coach Ja'Juan Seider and Holgorsen "just told us that this game could really come down to me and Wendell, that we could take control, that we could win it.
"We felt like we wanted that task and felt that we handled it perfectly."
Holgorsen improved to 2-2 as West Virginia's coach against Texas Tech coach Kliff Kingsbury.
Kingsbury was the Red Raiders' starting quarterback from 2000-02, when Holgorsen was the team's wide receivers coach. Holgorsen was the offensive coordinator at Houston in 2008 when he helped Kingsbury join Kevin Sumlin's staff.
Texas Tech, which had exceeded 50 points five times this season, was held to a season low for points and yards (378).
West Virginia's defense "exceeded what my expectations were defensively just because how potent these guys are," Holgorsen said.
Texas Tech's Patrick Mahomes was held to a season-low 196 passing yards but took advantage of West Virginia's 3-3-5 defensive scheme by running for a season-high 73.
Mahomes threw a 17-yard scoring pass to DeAndre Washington that pulled the Red Raiders within 31-26 with 6:47 left in the game.
But Texas Tech never got the ball back.
Smallwood had a pair of big runs on third down to keep the ensuing drive going. And when Texas Tech's Micah Awe was flagged for ripping West Virginia quarterback Skyler Howard's helmet off following a run, the Mountaineers got a first down at the Red Raiders 1 and subsequently ran out the clock.
Howard threw two interceptions and didn't have a touchdown pass for the first time this season. But it didn't matter considering how Smallwood and Shell were running against a defense that had allowed an average of 271 yards on the ground.
"It's been a rough season for the rush defense," Kingsbury said. "We're just not getting it done up front against the run for the most part. They exploited us in that area and held the ball a lot."
Washington finished with 102 rushing yards to become the first Texas Tech running back to go over 1,000 yards in back-to-back seasons since Byron Hanspard in 1995 and 1996.
Texas Tech's Jakeem Grant, who had 178 receiving yards and a kickoff return for a score a week earlier against Oklahoma State, was limited to five catches for 8 yards. He averaged 26 yards on five kickoff returns.
Mahomes had two first-half scoring passes, but the Red Raiders got no points on two other trips inside the West Virginia 25 in the second quarter and had to settle for a pair of second-half field goals after getting interceptions and driving inside West Virginia's 20.
"We were just bad in the red zone," Kingsbury said. "I'll take that on me. We've got to make plays and limit mistakes."
AP college football website: http://collegefootball.ap.org
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