OAKLAND — A lot can change over the course of a season and no one learned that lesson harder than Mt. Blue on Friday.

Mt. Blue got the better of Messalonskee when the two teams met three weeks into the season in Farmington. The Eagles returned the favor on their home field, hammering the Cougars 48-28 in an Eastern Class B quarterfinal game. Messalonskee will play at Brunswick in the semifinals.

Messalonskee (5-4) didn’t dig deep into its playbook — and it didn’t need to with the way Jack Bernatchez was running the football. The 6-foot-2, 185-pound running back ate up huge chunks of yardage with every carry, shaking of two or three arm tackles seemingly every play. Bernatchez finished just shy of the 300-yard mark, carrying the ball 27 times for 293 yards and five touchdowns. The Cougars finished with 277 yards of total offense.

“This offense is geared to angles and we took advantage of our angles and traps and that’s what we try to exploit every week,” Messalonskee coach Brad Bishop said. “We only ran two formations and three plays, I think.”

Mt. Blue (4-5) started with a bang when Nate Pratt-Holt returned the opening kickoff 85 yards for a touchdown. The defense forced a turnover on Messalonskee’s first drive when quarterback Jake Dexter was stripped of the football inside Mt. Blue’s 20.

But Bernatchez put an end to Mt. Blue’s upset hopes, scoring a pair of touchdowns late in the first quarter to give Messalonskee a 14-7 lead. In their regular-season loss to the Cougars, the Eagles mustered just seven points.

“We were finishing this week,” Bernatchez said. “Last time we played them, we lost two goal-line drives and this time we converted.”

Mt. Blue tied the game at 14 on a 1-yard dive by running back Zach Meader in the second quarter, but the defense couldn’t slow down Messalonskee’s running game. Bernatchez scored his third and fourth touchdowns of the night within a span of 2:32.

“It boils down to blocking and tackling,” Bishop said. “You can throw any defense out there. We feel like we have a scheme to block it and the kids have to execute it. We worked on five different defenses this week because we didn’t know what they were going to run.”

It took just six carriers for Bernatchez to hit the century mark and he amassed 171 yards by halftime.

It was more of the same in the second half. The Eagles ran the ball down the field on their opening possession and capped it off with a 24-yard touchdown pass from Jake Dexter to Colby Dexter for a 34-14 lead.

Pratt threw a pair of second-half touchdowns — a 7-yard strike to Pratt-Holt and a 77-yard connection to Christian Whitney. But the Cougars never got closer than 13 points in the second half. Pratt finished 10-for-18 for 144 yards.

“When you give up 48 points you don’t win a whole heck of a lot of football games,” Mt. Blue coach Jim Aylward said. “It’s just that simple. We tackled very, very poorly. Coach Bishop is a good coach. Their offense, they run the same five plays and if you can’t get off a block and you can’t tackle, you lose.”

Bernatchez finished his night with a 3-yard run up the middle with 9:02 remaining in the game for his fifth touchdown of the contest. He sat out the final two drives.

“We’re older,” Bishop said. “We’re still young but we’re more experienced and injury free. They played hard. These kids dig down, they play hard. We make mistakes but a win’s a win. The kids are more experienced. That’s what you can chalk it up to.”