PORTLAND — Whether No. 11 Wells’ 43-42 win over No. 3 Spruce  Mountain was an upset depends on where one stands on an age-old debate regarding the relative merits of the Western Maine Conference and the Mountain Valley Conference.

Wells rebounded from a 12-0 deficit to start Tuesday’s Western Class B girls’ quarterfinal and shut down Spruce Mountain over the final three quarters to pull off the bracket buster and hand the Phoenix their first loss of the season.

Allison Furness and Jordan Agger led the WMC-forged Warriors (9-11) with 11 points apiece. They will face second-seeded York in the semifinals on Thursday.

Nicole Hamblin led the MVC-molded Phoenix (18-1) with 12 points, while Emily Keene chipped in with 10.

The two teams faced each other in a Christmas tournament at the Expo, which Spruce Mountain won by two. The Phoenix were playing Tuesday without injured starting forward Victoria Ouellette, who was a key to defending Furness in that win.

Wells was ready for whatever Spruce Mountain had in store.

“We had a little idea of what we were going against, but from Christmas time to now, we’ve improved tremendously,” said junior forward  Sophie Lamb, who had three big points and a huge rebound in the fourth quarter. “Spruce Mountain, we think they’ve had kind of an easier schedule. We’ve played against (fellow B West tournament teams) York, Lake Region, Greely. I mean, they’ve gotten us really tough for the tournament.”

The Warriors toughened up some more on Tuesday.

Nicole Moody made the front end of a one-and-one to give the Warriors a 41-37 lead with 53 seconds left. Lamb rebounded her miss on the second try. The Phoenix fouled Furness immediately and lost the rebound out of bounds when she missed the front end of her one-and-one. The Phoenix did get the ball back when Moody missed the front end of her ensuing bonus freebies, but the expired time would come back to haunt the Phoenix.

Hamblin rattled in a 3-pointer to make it 41-40 with 21 seconds remaining. Lamb made one of two from the line and Spruce traveled on its ensuing possession, forcing a quick foul of Agger with 8.9 seconds to go.

The sophomore made one of two and the Phoenix, electing not to take a time out, sprinted down the court for a game-tying 3-pointer. Inexplicably, however, they drove the lane for a runner that didn’t draw iron. Keene’s putback at the buzzer left them a point short.

“Unfortunately, we just were not thinking the time and score situation at the end of the game,” Spruce Mountain coach Gavin Kane said. “We wanted to push it in transition to make them scramble defensively.  Unfortunately, we attacked the basket instead of looking for a 3-pointer.”

Spruce Mountain started the game just as aggressively. It sprinted out to the 12-0 lead led by as much as 13 before Furness scored Wells’ first field goal with 2:25 left in the first quarter.

“I was very impressed with our trapping and our pressure. We got them to throw the ball around a little bit,” Kane said. “But then we backed off a little bit. It’s been a tendency of ours when teams go on a little bit of a run to put our heads down instead of really digging down deep and grinding it out and wanting to continue to play with that same aggressiveness.”

“In the first quarter, we play like we always do, but we were all really nervous,” Lamb said. “After we got the feel of it, we just kept bringing that pressure. We just started to do it clean.”

The Phoenix took a 19-9 lead into the second quarter but came apart at both ends of the floor. Samantha Richards went to the bench with her second foul and Moody and Furness attacked the basket to quickly cut into the deficit, and a steal and layup by Stephanie Woods pulled the Warriors within four at halftime.

“They started to really attack us very well, and not having Sam in the back of our trap or in the back of our zone, that opened things up a little for them as well,” Kane said. “On the offensive end, we’re very sporadic. We got a little tentative and stopped looking to attack.”

Wells closed the third quarter with an 11-0 run, taking the lead for the first time, and for good, on a nice feed from Woods inside to Moody to make it 31-30 with 1:55 left in the period.

“It took us a little while to sort out their pressures,” Wells coach Don Abbott said. “What I told the girls was, ‘Listen, Spruce Mountain is a good pressing team. You’ve played against a lot of good teams that have a lot of good pressure all year long.”

“In all reality, they play a stronger schedule overall,” Kane said. “Yes, we constantly hear that B schools from the Mountain Valley Conference don’t necessarily deserve to be down here. But I disagree totally with that.”

“Unfortunately, we just were not thinking the time and score situation at the end of the game,” Kane said. “We wanted to push it in transition to make them scramble defensively.  Unfortunately, we attacked the basket instead of looking for a 3-pointer.”