BANGOR — Maine Central Institute rallied for its biggest boys’ basketball tournament win in years, overcoming an eight-point halftime deficit to beat Oceanside, 58-52, in overtime Saturday morning in a Class B North quarterfinal at Cross Insurance Center.

No. 5 MCI (15-4) advanced to the semifinals for the first time since 2008 and will face either No. 1 Hermon or No. 8 Presque Isle in the semifinals at 3:35 p.m. Wednesday. No. 4 Oceanside ends the season at 13-6.

“It was amazing. I didn’t know what to say,” said MCI senior Jaroslav Ruta, who came off the bench to score 22 points and grab 11 rebounds. “This could be my last game, so I put in everything I’ve got.”

Joe Cloutier’s elbow jumper with 50 seconds left in the fourth quarter gave MCI a 43-41 lead. Cooper Wirkala (18 points) hit a layup with 28 seconds left, and MCI’s Daniel Garamvolgyi’s jumper as time expired was short.

MCI scored the first six points of overtime, taking a 49-43 lead on a Gavin McArthur layup with 2:15 left. The Mariners cut the deficit to 51-48 on a pair of Wirkala free throws with 1:32 to play, but that’s as close as they got.

Down 25-17 at the half, MCI needed a wakeup call. Open shots didn’t fall in the first half, and the Mariners outworked the Huskies for 50-50 balls and rebounds. Oceanside grabbed 23 rebounds in the first half to MCI’s 14.

“Frankly, that’s been our Achilles. For as big as we are, at times we don’t get after it with rebounds. That’s effort, and sometimes it’s execution. We just didn’t get it done,” MCI Coach Josh Tardy said. “We did a better job in the second half, although I still think there’s plays out there that we’d like to have that.”

MCI cut Oceanside’s lead to 33-29 entering the fourth quarter. Hayden Caldwell’s fast-break layup on a pass from McArthur tied the game at 41-41 with 1:26 left. The basket was one of many the Huskies made in transition, beating Oceanside’s full-court pressure.

“We’re pretty good against pressure. That sometimes is our best offense. We just have to attack. We get good spacing and guys finish. We didn’t finish in the first half. We finished in the second half,” Tardy said.

Added Cloutier: “We had to step up our intensity. We came out a little flat. Our offense wasn’t flowing … We said, we’re faster than them. Why not bust out and take advantage of it?”

Cloutier’s jumper with just under a minute left gave the Huskies their first lead since early in the second quarter, but Wirkala answered. Oceanside’s high scorer was kept in check for much of the game by MCI’s triangle-and-two defense, but he scored 13 of his 18 points in the fourth quarter and overtime, including all nine of the Mariners’ overtime points.

“It wasn’t anything we shouldn’t have been able to handle,” Oceanside Coach Matt Breen said of MCI’s defensive strategy. “We’ve got other players who can step up and make plays. We were doing it to a point, and then we lost our composure a little bit.”

For Oceanside, this game goes on the list of Cross Insurance Center heartbreaks. The Mariners are 0-4 there in tournament games, with two overtime losses, a loss on a buzzer-beating putback to Winslow last season, and another close loss to Winslow.

“We were doing all right. We were up eight. We were trying to spread them out, and I was trying to get penetration. We’d had plenty of success penetrating against them when they were going one on one,” Breen said. “We kind of started going east and west instead of trying to score the basketball. It just comes down to execution, and they just executed better down the stretch.”

Jack Lombardo added 11 points for Oceanside. Trevor Reed had 14 rebounds.