AUGUSTA — After starting slowly in the quarterfinals, the North Yarmouth Academy girls’ basketball team did just the opposite Thursday in its Class C South semifinal against Winthrop.

The Panthers raced to a 14-5 lead after one quarter and held a commanding 28-10 advantage at the half. That cushion was more than enough, as third-seeded NYA advanced to its first regional final in two decades with a 55-34 victory over the No. 2 Ramblers at the Augusta Civic Center.

It’s been even longer since NYA won its only regional title, in Class D in 1982.

Catherine Reid and Serena Mower stuffed the stat sheet, and Helen Hamblett, Sydney Plummer, Katie Larson and Maggie Larson hit clutch shots to help the Panthers improve to 16-4 and set up a showdown versus top-seeded Boothbay (20-0) in the regional final at 7 p.m. Saturday in Augusta.

“We saw last game how important it was to come out strong and play from ahead, so today we knocked down our outside shots and we attacked the rim,” said Reid, who finished with 14 points, 11 rebounds, nine steals and six assists. “When we do that, we’re tough to stop.”

Reid got things going with a basket off a steal 22 seconds in, then added a jump shot. NYA led 7-5 after a jumper by Winthrop’s Kena Souza, but Hamblett made two free throws, Maggie Larson sank a 3-pointer and Reid made a layup after a Mower steal for a 14-5 lead after the first period.

While Winthrop (17-3) was held scoreless for nearly nine minutes spanning the first and second quarters, NYA stretched its lead to 18 points at halftime. Reid recorded 10 points, six rebounds and three assists in the first half.

Maggie Larson and Reid, along with Carly Downey, are new to the Panthers’ program this winter, coming over from Maine Girls’ Academy, which closed last summer.

“It was nerve-wracking at first with all the eyes on us, but we’ve adjusted to each other really well,” said Maggie Larson, who scored 11 points. “It’s nice to have (Catherine and Serena’s) sturdy presence.”

The Ramblers showed some life to start the second half, scoring eight consecutive points, highlighted by six from Souza. But Mower got a jumper to bounce in, Reid set up Plummer for a layup, Reid hit a runner, Mower and Katie Larson each made two foul shots, and a layup after a steal by Reid made it 40-18.

“We came out of the locker room without any quit and we got it to 10, but with us expending that much energy, (NYA) stayed the course and got the lead back up,” said Winthrop Coach Joe Burnham. “They have a nice collection of players.”

Mower finished with eight points, six steals, six assists and four rebounds. Katie Larson added eight points, and Hamblett and Plummer each scored six.

“I’m extremely proud of the kids and how far they came,” Burnham said. “It’s one of my favorite seasons to be a part of, not just the winning but because of the type of kids in that locker room.”