BOZEMAN — For the first time all season, Montana State allowed a visiting opponent to score in the first quarter of a game played inside Bobcat Stadium.

It made little difference, as the Bobcats used a flurry of touchdowns to close out the first half en route to a 52-19 win over Idaho on Saturday in the quarterfinal round of the FCS playoffs. Montana State will play a semifinal game next Saturday for the fourth time in six years.

The top-ranked and undefeated Bobcats started the game against the Vandals in typical fashion of this historic season — marching down the field on the opening series to score a touchdown on a 3-yard pass from quarterback Tommy Mellott to tight end Rylan Schlepp.

The game seemed to turn late in the first quarter, though. Idaho quarterback Jack Layne, who missed the Vandals’ regular-season loss at Montana State, aired out a pass to a wide-open Jordan Dwyer.

Dwyer, who was running free behind the MSU secondary, caught the perfectly placed pass and ran in for a 55-yard touchdown. Idaho and Montana State were tied 7-7 going to the second quarter.

The teams traded field goals in the second — Myles Sansted converted from 46 yards for Montana State and Cameron Pope made a 32-yarder for Idaho — but the wheels came off for the Vandals in the waning minutes of the half.

Following Pope’s field goal, Idaho coach Jason Eck opted to go for a surprise onside kick. The ball didn’t travel the required 10 yards, giving the Bobcats the ball at the Idaho 38-yard line. Montana State capitalized, with Mellott scoring this time on the ground from 8 yards out to give the Bobcats a 17-10 led with 3:47 to play in the first half.

On Idaho’s ensuing possession, Mark Hamper fumbled on a wide receiver screen after running into the back of one of his own blockers. MSU defensive end Brody Grebe recovered the fumble, and the Bobcats’ offense came back on the field.

Moments later, running back Adam Jones, who started in the absence of Scottre Humphrey, was in the end zone, and the Bobcats were suddenly up 24-10.

But the first-half disaster wasn’t over for the Vandals. Idaho was forced to punt, and — after a 15-yard return by Taco Dowler — Mellott showed why he’s a finalist for the Walter Payton Award.

The senior from Butte dropped back to pass but didn’t find an open receiver. With pressure closing in, Mellott scrambled through an opening in the line, juked an Idaho defender and sprinted down the left sideline. He was forced out 63 yards later, and the Bobcats were in business inside the Idaho 5-yard line with less than 30 seconds left in the half.

Jones eventually punched in another touchdown on third-and-goal, and Montana State took a 31-10 lead into halftime, having scored 21 unanswered points in less than four minutes of game action.

The second half didn’t start much better for Idaho. Layne threw an interception to Jon Johnson on the Vandals’ first offensive play, and five minutes later Jones scored this third touchdown, this one from 9 yards out. Mellott added a 5-yard TD pass to Dowler later in the third, and Montana State took a 45-10 lead to the fourth quarter.

Less than a minute into the fourth, Jones added another touchdown. After taking a Mellott pass 56 yards to the 2-yard line, Jones scored his fourth TD of the night on the next play.

Layne and Dwyer connected for another Idaho touchdown in the fourth quarter, and Pope added a 43-yard field goal.

Montana State improved to 14-0 for the first time in program history, and the 14-game win streak is also the best in program history. Fourth-year head coach Brent Vigen is now 30-1 during his career at Bobcat Stadium and has guided Montana State to the semifinal round of the postseason in three of his four years.

Idaho, which was the eighth seed for this year’s playoffs and entered Saturday’s game with a six-game winning streak, finishes the season at 10-4.

Turning point: Hamper’s fumble completely changed the complexion of the game. It was just a one-score game when Idaho started the series with an opportunity to close out the half. Instead of driving the field and getting points, the turnover gave the Bobcats a short field and started the avalanche that finished out the first half.

Stat of the game: Montana State dominated in all facets, and perhaps nothing illustrates that more than the teams’ performances on third down. The Bobcats converted on 11 of 15 third-down plays, while Idaho was only 2 of 10, with its first successful third-down conversion coming in the fourth quarter against Montana State’s second-string defense.

Bobcat game balls: RB Adam Jones (Offense). With Humphrey sidelined, Jones, the Big Sky Conference freshman of the year, showed he was more than capable. He handled the bulk of the carries, finishing with 23 totes for 95 yards and four touchdowns. He also had three catches for 66 yards. Jones, a graduate of Missoula Sentinel High School, now has 1,068 rushing yards on the season.

DE Brody Grebe (Defense). Grebe started the game blowing up a fourth-down run on Idaho’s first possession to keep the Vandals off the scoreboard in the early going. And his fumble recovery in the second quarter was one of the pivotal plays of the game. The official stats gave Grebe only one tackle, but his imprint was all over the game.

What’s next: Montana State will have its final home game of the season at 1:30 p.m. on Saturday, Dec. 21, against either UC Davis or South Dakota in the semifinal round. The Coyotes host the Aggies at 1 p.m. on Saturday in a quarterfinal game.