BOISE, Idaho (AP) -- Ian Johnson finally got on track, and what a difference it made for Boise State's offense.
Johnson gained 111 yards on the ground and scored three touchdowns Thursday night in Boise State's 38-16 victory over Southern Mississippi. But he was just as dangerous as a receiver,
catching three passes for 80 yards. His biggest catch helped put the game away when he grabbed a short pass in the flat and turned up-field for a 54-yard gain.
He scored two plays later, taking the ball off right tackle and running two yards untouched.
After Johnson's slow start in the season's first three games, Broncos coach Chris Petersen said the difference this time was simple: create opportunities in the open field and let him take it from there.
"The real key to the whole thing was to get Ian some space," said Petersen, whose team improved to 3-1 and opens Western Athletic Conference play Oct. 7 against New Mexico State.
"In the pass game and the running game ... when that guy gets space, he's going to get it going," Petersen said.
Boise State also benefited from the heady play of quarterback Taylor Tharp.
Tharp's crisp passing early helped the Broncos score on their first two possessions and take a commanding 28-10 lead at the half.
In his fourth career start, Tharp finished 19-of-27 for a career-high 307 yards and two TDs. While blessed early with short fields, Tharp also led the Broncos on drives of 75 and 79 yards and guided an offense that rolled up 506 total yards. His lone interception was underthrown and picked off in the end zone by Brandon Sumrall as the Broncos were driving late in the first quarter.
"After four years as a backup it is really hard to get yourself into that mode and get a feel for the game," Tharp said. "Having a few games under my belt is a huge difference. I feel like my game just keeps rising and there is a lot of potential there."
For the Golden Eagles (2-2, 1-0 Conference USA), the loss raises some concerns.
The defense, stung several times already this year by big plays, yielded several more, including Tharp's 42-yard bomb to Titus Young that set up another Broncos touchdown and Johnson's 54 yard catch that set up Boise State's final touchdown moments after Southern Miss scored to pull within 28-16.
"We did keep our poise for a while," said coach Joe Bower. "Then we gave up the huge play (to Johnson) and it turned things around just like that."
Falling behind early also shifted the offensive focus away from running back Damion Fletcher, who rushed for 1,692 yards last season, 11th best in the nation. Fletcher rushed for 83 yards on 21 carries, and aside from a 22-yard run in the second half struggled to find running room.
Southern Miss also lost starting quarterback Jeremy Young, who exited midway through the third quarter after rolling his ankle in the open field. Young, who was 13-of-23 for 190 yards and a touchdown, returned to the sidelines on crutches. Bower said Young's high ankle sprain will keep him out of the Oct. 3 game against Rice.
The Golden Eagles gained 318 total yards on offense and turned the ball over twice.
Boise State scored on its first two possessions, the first when Tharp tossed a 14-yard TD to Jeremy Childs. On the second, Tharp capped an 11-play, 54-yard drive by lofting a 2-yard TD to tight
end Richie Brockel.
After Johnson scored on a 12-yard run in the second, Boise State capitalized on Young's muffed snap deep in Southern Miss territory. Two plays later, Johnson took a pitch left, eluded a tackler and dashed to 22 yards to put Boise State in front 28-3.
But Southern Miss closed late in the half when Fletcher capped an 80-yard drive with a 1-yard plunge, making the score 28-10.
And on their first possession in the third quarter, the Golden Eagles marched down the field 75 yards and scored when Young fired a 23-yard strike to Shawn Nelson to pull within 28-16.
With Young on the sidelines, the Golden Eagles were unable to get any closer.