While far removed from another Bowl Championship Series appearance, Utah is still on the fringe of contending for the Mountain West title thanks to four straight victories.
Mack pounded his way for 100 yards rushing with a score -- on 32 carries -- and Johnson threw a touchdown as the Utes beat TCU 27-20 on Thursday night. Mack's fourth straight 100-yard game and Johnson's return from injury coincide with the winning streak.
"Getting Brian Johnson back was huge," coach Kyle Whittingham said. "He's a team leader, someone to rally around. He's unquestionably our field general."
After missing all of 2006 following knee surgery, Johnson separated his shoulder in the season opener and missed three games. While he was out, Utah suffered its first shutout loss in 14 years.
The Utes (5-3, 2-2 MWC) planned for Mack to redshirt this season, and the two-time letterman didn't even play in the opener. That changed when Matt Asiata broke his leg and Mack has since run for 100 yards in five games -- all of Utah's victories.
"Darrell is doing an awesome job. It wasn't pretty tonight, but it was effective," Johnson said. "He's got a lot of confidence. I hope we keep it rolling."
TCU (4-4, 1-3), with three 11-win seasons the past four years, already has three losses to teams ahead of the Horned Frogs in the Mountain West standings.
Chris Manfredini kicked a 41-yard field goal for TCU with 2:07 left and the Frogs thought they had the ball back when David Hawthorne recovered an onside kick. But officials ruled Hawthorne touched the ball before it went 10 yards, and confirmed that after a lengthy replay review.
Since TCU had already used all of its timeouts, Johnson got to down the ball three straight plays to run out the clock -- and the Utes celebrated another victory.
"You can see the swagger and confidence starting to build in these guys," said Johnson, who was 13-of-20 for 120 yards. "It's contagious."
The last time Utah had a longer winning streak was the 18 in a row that included the undefeated 2004 season that made the Utes the original BCS buster. Utah's school-record winning streak ended in a 23-20 overtime loss at TCU in 2005.
Andy Dalton, the redshirt quarterback who won TCU's starting job in preseason drills, was 20-of-45 for 159 yards with four interceptions. He had been picked off only four times his first six starts and was coming off a 344-yard game in a win at Stanford.
"If you turn the ball over as many times as we did, you aren't going to beat a junior high team," coach Gary Patterson said. "I thought we came out flat. I thought the cheerleaders, band and student section were great."
Martail Burnett, Utah's 262-pound senior defensive end, returned one of the interceptions 55 yards for a touchdown with 54 seconds left in the first half. It was Burnett's first career interception and put Utah ahead 24-14.
"He threw it right at me," Burnett said. "I saw the end zone and I wanted to dive, but I was too tired."
Louie Sakoda's 41-yard field goal midway through the fourth quarter was Utah's only score after halftime.
Mack's 1-yard TD run capped an game-opening 58-yard drive, and Sakoda kicked a 31-yard field goal after Dalton's first interception.
The Horned Frogs used special teams and a trick play early in the second quarter to erase a 10-0 deficit.
Daryl Washington blocked his third punt of the season, deflecting Sakoda's kick straight up into the air. The ball bounced into the hands of Stephen Hodge, who returned it 31 yards for a touchdown.
After Brian Bonner's 30-yard punt return, Dalton handed off to Jeremy Kerley sweeping right. Then it was a throwback to Dalton, who gained 27 yards to the 1 to set up Marcus Brock's TD run that put TCU up 14-10.
Utah went ahead to stay at 17-14 when Johnson threw a 24-yard TD to Marquis Wilson with 3:20 left in the first half.
Manfredini, who later missed a 22-yarder, made it 24-17 with a a 37-yard field goal on the final play of the first half.