PORTLAND — Eight seniors strong, Wells has that look in its eye this girls’ basketball postseason, one that combines confidence and talent with something that borders on fury.

As was the case with previous victim Gray-New Gloucester, the corresponding countenance of Spruce Mountain was one of anxiety, then timidity, eventually shell shock.

No. 2 Spruce Mountain’s undefeated girls’ basketball season and championship hopes consequently ended in resounding fashion Thursday afternoon in a 55-31 loss to No. 3 Wells in the Class B West semifinals at Cumberland County Civic Center that wasn’t nearly that close.

The Phoenix offense gradually trickled to a stop throughout the game — eight points in the first quarter, five in the second and two in the third — while the Warriors poured it on with a clinic at both ends of the court.

“Impressive team, for sure. A veteran group like that, I’ve said from early in the year that was a team that could win it all. They have all the pieces of the puzzle,” Spruce Mountain coach Gavin Kane said. “You can’t be tentative against a team like that. I thought we were, and they fully took advantage.”

Alison Furness has been the player of the tournament so far, and the 5-foot-10 senior’s game lost nothing in the two-mile transition from Portland Expo and Wednesday’s 49-30 quarterfinal rout. She erupted for 15 of her game-high 21 points in the first half Thursday and didn’t even set foot on the floor in the fourth quarter after Wells ripped open a 50-15 lead.

It was 15-8 after one quarter and 32-13 at the half before that.

Wells, which eliminated Spruce Mountain in the 2013 quarterfinals before losing to York by two points, will face No. 1 Lake Region at 2 p.m. Saturday in the regional final. The Warriors are the only team to defeat the Lakers this season.

“We came here with one goal. That’s to make Western Maine and go to states, and we’re not going to stop,” said Wells senior forward Sophie Lamb, who added eight points and eight rebounds. “In preseason this year (Spruce Mountain) beat us by two or three or four. I don’t even remember. We just wanted to let them know that’s not going to happen. We’re a totally different team. Our defense was awesome.”

Spruce Mountain was harassed into two dozen turnovers, many of them in its half-court offense and a majority leading to easy layups. Wells guards Nicole Moody and Stephanie Woods combined for 11 steals.

Kailee Newcomb led the Phoenix with seven points. Rylee Moore and Brooke Tracy each added six, all in the fourth quarter.

“They put a lot of ball pressure on us in their man-to-man, and their matchup zone frustrates a lot of teams as much as it did us today,” Kane said. “You really have to have great movement against them, and we didn’t have that. It certainly played into their hands.”

Newcomb put Spruce Mountain on the board first with a 18-foot jumper. But Wells, in a complete reversal of last year’s win that required a second-half comeback, answered with nine straight.

Recurring themes developed quickly. Furness started the surge with a 3-pointer. Lamb scored courtesy of the offensive glass. Moody turned a steal into an uncontested hoop. All of it happened in under a minute.

Furness capped the run with two free throws.

“Playing two games in two days, we just kind of drew off what we did yesterday. We established a blueprint for being successful,” Wells coach Don Abbott said “When we get some stops, we can run, and when we can run, we can be pretty dangerous in the open floor.”

Spruce Mountain whittled the deficit to three at 11-8 on back-to-back drives by Nicole Hamblin and Emily Keene. Lamb scored again and Jordan Agger drained two free throws to restore the Warriors’ breathing room.

Furness drained another 3-pointer in a nine-point second period. So did Woods and Meghan Young, while the Phoenix went the final five minutes without a field goal. Wells pitched a shutout for the concluding 4:27.

“We were ready for a battle. All our energy just immediately went out on the floor,” Furness said. “We did really well talking. We stayed on our feet. We moved a lot. When we’re all in sync, it works out really well. That happened tonight. It was great.”

All aspirations of a Spruce Mountain comeback evaporated in Wells’ 18-2 domination of the third period. The Warriors finished the period with 15 straight points, punctuated by freshman Allyson O’Brien’s 3-point play.

Spruce Mountain was making its first semifinal appearance in school history after quarterfinal losses to Leavitt and Wells the past two years.

“It’s a better feeling than 364 days ago when we lost by two to York here, but I said to the kids, rah-rah for that experience,” Abbott said. “You don’t get here very often, and it is different. Our kids seemed to feel a bit more comfortable from the beginning of the game out on the floor.”

The loss ends a brief but phenomenal run for the Phoenix in the Mountain Valley Conference. They’ll move to the Class B-dominated Kennebec Valley Athletic Conference next season in hopes of being better prepared for playoff competition.

In its three years, Spruce won two titles and was 53-1 in regular-season play. That preseason win over Wells in a tournament at McAuley might have supplied a measure of comfort, but from the tap it was apparent that the Warriors were a decided step up from the games of December and January.

“Defensively we threw just about everything but the kitchen sink at them, and they handled it all,” Kane said.