Tied 21-21 at the half with twelfth-ranked Montana on Saturday, No. 11 Appalachian State made key plays on offense and defense down the stretch in the clutch.
The Mountaineers (1-1) got a late fourth-quarter touchdown run from running back Steven Miller and also made a stand on defense with an interception by Demetrius McCrary to pick up a 35-27 victory over the Grizzlies at Kidd-Brewer Stadium.
"I think everybody realized this was a great win for our team, program and our school," said ASU coach Jerry Moore. "We've had great games with Montana in the past, but today we played extremely well and made a great stride from last week".
After trailing by a touchdown early to the Grizzlies, Appalachian State scored on three-straight first quarter possessions to jump out to a 21-7 lead.
Quarterback Jamal Jackson had two of those touchdowns, including a 32-yard pass to Sean Price, as well as a five-yard run.
Miller added the other touchdown run on a 13-yard dash.
Montana (1-1) rallied back to tie the game before halftime with 14-unanswered points in the second quarter.
Grizzlies signal-caller Trent McKinney took a 10-yard run into the end zone less than two minutes into the second quarter.
McKinney wasn't finished in the quarter, as he helped Montana add another tally with 35 seconds remaining until the break, finding Sam Gratton on a seven-yard strike to knot the game 21-21 at halftime.
A scoreless third quarter would help set up a dramatic finish in Boone.
Jackson guided the Mountaineers in taking a touchdown advantage with a 25-yard touchdown pass to Andrew Peacock with 13:03 remaining in the game.
McKinney, who finished Saturday's game with 307 passing yards, three passing touchdowns and three interceptions, answered for Montana on an one-play drive that ended with an 87-yard hook up to receiver Dan Moore.
ASU stayed mentally tough, responding on a 11-play, 78-yard drive capped by Miller's two-yard scamper for the eventual game-clinching touchdown.
"Coach Moore had been preaching about how important this game was, and it put a lot of pressure on our offensive linemen, but those guys blocked well today," Miller said. "Sometimes, the holes weren't as good due to the blitzing by the defense, but on the zone reads, the holes were extremely large, allowing me to hit it hard and fast up the middle".
With 2:53 left on the clock, McKinney drove the Grizzlies down to the Mountaineer 42-yard line, but McCrary intercepted his second pass of the game on a second-down heave to close out the Appalachian State victory.
"In 2009, when I was a freshman, we went up to (Montana) and we lost," said McCrary, who finished with three tackles to go along with his pair of picks. "So today was like revenge. We really wanted to beat these guys to avenge the 2000 and 2009 losses to them. I guess you could call it a revenge game."
Jackson led the Mountaineers with 260 passing yards on 24-of-34 attempts with two touchdowns and no interceptions.
On the ground, Miller had 27 carries for 99 yards and two scores.
The Mountaineers play another home game 3:30 p.m. next Saturday at "The Rock" when they start SoCon play against The Citadel (2-0, 1-0).