WATERBORO — Funny how things work out.

Back in the winter of 2003-04, Brooks Bowen and Jason Tremblay, two newer teachers at Massabesic High, thought the school should form lacrosse teams.

Neither man had a lacrosse background, but they had a plan. Tremblay, a hockey coach, would coach the girls’ program. Bowen, with his football background, would take the boys.

“Then we had 25 girls show up with sticks and cleats ready to go and only three boys,” Tremblay said with a laugh.

They decided to join forces and start a girls’ team with Bowen as the head coach and Tremblay as his assistant.

“And 12 years later, here we are,” Bowen said.

The Mustangs are the defending Class A champions and this year’s top seed in Western A. They are the two-time defending regional champs and also won a state title in 2007, during a time when many other Massabesic athletic programs have struggled.

“I know for myself, people sometimes say, ‘Oh, you play sports at Massabesic, that must be tough,’ ” said Mira Kuni, a defender and one of the four senior captains. “I just say, ‘Hey, I play lacrosse. We won states last year. We’re not all bad.’ ”

After beating Sanford 17-1 in Wednesday’s regional quarterfinal, Massabesic (11-2) will host No. 4 Scarborough (9-4) in the semifinals at 7 p.m. Saturday.

The Red Storm can expect to be greeted by a loud pro-Mustang crowd.

“Last year for our regional final we had a crowd three people deep all around the field,” said co-captain Karlie Pike. “It’s so touching to know our community supports us.”

A year ago, Pike assisted on the sudden-death goal to defeat Thornton Academy in the regional final, then scored the winner in the fifth overtime to beat Cheverus 9-8 in the state final.

“You know (Massabesic is) going to give their best effort and they’re going to make you work for everything,” said Thornton Academy Coach Craig Agreste. “They play aggressive but they play clean. They’ve done a heck of a job building that to where it is. It’s because they teach the skills, they teach the fundamentals and they get the very best out of their athletes.”

Mackenzie Kidder at attack and four-year starting goalie Megan Hill are Massabesic’s other two captains. They both pointed to the ability of Bowen and Tremblay to push the right motivational buttons.

“I think the coaches and the girls want it, want to be successful,” Kidder said. “We all want it but the coaches, their expectations are a little higher, so we all build on it.”

Scarborough (four), Brunswick (two) and Massabesic are the only schools with multiple Class A girls’ lacrosse state titles since the sport split to two classess in 2006. Bowen’s teams have made the playoffs in 10 of 12 years with one losing season.

“I’m glad Jason’s still here. I’m glad we did it together,” Bowen said. “I think it’s a testament to the construction of the feeder program and a testament to the quality of the athletes who come through it, and our ability to adjust to new concepts and the athletes that we have any given year.”

Continued success seems likely. Varsity team members are actively involved as coaches in the Massabesic Filly Lacrosse for girls in grades 2 through 5.

“Now we’re starting to see freshmen coming in who have played five and six years,” Kidder said.

“I think we have set the bar,” Hill said. “It’s nice to be part of this team. You take so much pride in being a player for Massabesic girls’ lacrosse.”

This season, Massabesic’s two losses came in overtime – one at Class B contender Kennebunk, the other at home to Scarborough. If the Mustangs get by Scarborough, they will host No. 2 Marshwood or No. 3 Thornton, teams they beat by one and two goals, respectively.

Junior attack Maquila Dimastrantonio led the Mustangs with 55 points in the regular season. Delia Sylvain was the second-leading scorer. Kidder, Pike and several others consistently provide offensive threats.

Senior Allison Cahill joins Hill and Kuni to spearhead an experienced defense. Younger players Maddie Drain and Emma Desrochers have joined former defender Maddie Russell to solidify the midfield.

Now Bowen is looking for a postseason push built on the effort that has come to define Mustang lacrosse.

“It started with our work ethic and it’s probably going to end there also,” Bowen said. “We’ve always felt that you had to be willing to do what your opponents weren’t. That was what was going to separate you.”