MANCHESTER — The Bishop Guertin of Nashua girls’ basketball team has had Division I in its clutches for years now. The Cardinals are a game away from tightening that stranglehold and continuing a string of dominance NHIAA basketball rarely sees.

A 66-36 win over fourth-seeded Manchester Memorial in Thursday’s D-I semifinals at Stan Spirou Field House has the top-seeded and undefeated Cardinals in line to play for another title. BG can become the fourth school in Division I girls’ hoops history to win four straight championships if it can down sixth-seeded Portsmouth, which upset No. 2 Pinkerton in Thursday’s first semifinal, in Saturday’s 4 p.m. championship at Stan Spirou Field House.

“There’s nothing routine about this,” BG coach Brad Kreick said. “It’s just electrifying to be here and you never really get used to it, but I’m awfully glad we’re here. These kids sort of smell it and show up when it’s go time, which they did a nice job doing again tonight.”

There were very few holes in the the Cardinals’ effort. BG (20-0) generated 18 points off 17 Memorial turnovers while scoring 38 points in the paint to go with seven 3-pointers. An 11-2 run to end the first half spaced things out for BG as it led 33-19 at halftime before pouring it on with a 16-7 third-quarter edge.

“It was tempo. We were able to continue to have the game speed up a little bit,” said Kreick of breaking free in the middle periods. “We went eight players deep in the first eight or nine minutes of the game. I think we wanted to make it a 32-minute game and play up-tempo like we do.”

Addison Smith led BG and all scorers with 21 points, including 13 in the first half. Hannah Muchemore and Ava Owens joined Smith in double figures with 14 and 10 points.

Smith came off the bench to score seven of BG’s points during the Cards’ closing spurt in the second quarter.

“She’s been fantastic all year long, but unbelievable for us in the second half of the season,” Kreick said. “She’s such a versatile kid. We’ll put her on the block from time to time, but then she can step out and hit the foul-line jumper or 3-pointer. She’s a tough matchup for teams.”

Memorial (17-4) had Jennessa Brunette provide 10 points, but what hurt the Crusaders was getting just three points from D-I Player of the Year candidate Lyric Grumblatt. BG’s Aaliyah Foreman was draped over Grumblatt throughout the night, leaving the Memorial junior little room to create opportunities.

Memorial coach Greg Cotreau was the first to admit that BG simply wore his girls down. The Cardinals kept each of their starters under 25 minutes while the Crusaders were forced to play Brunette, Grumblatt and Jess Carrier for over 29 apiece.

“We were in it the whole first half,” Cotreau said. “I think the back-breaker was over-rotating to Gabby Sousa in the corner. She’s a kid we’re OK giving that shot to, but we’re not OK giving Addison Smith an open jumper on the wing. The dagger she hit at the end of the first half kind of took the air out of our sails a bit.”

Portsmouth 43, Pinkerton 41 (OT): Everyone knew about the stars on display when Portsmouth High and Pinkerton Academy met on Thursday. Matchups like Abbe Laurence versus Brooke Kane or Ani Hebert against Madison Mahoney were simply going to cancel out, leaving the game in the hands of role players.

Brittany Graham was the one who came to the forefront the most for Portsmouth as she hit a game-tying 3-pointer with three seconds to play and forced overtime. The Clippers picked up a bucket each from Hebert and Laurence in the extra frame while Portsmouth’s defense forced a pair of turnovers and a Pinkerton miss over the final 3:30 of overtime.

The Clippers, who returned to Division I this season after moving to D-II after the 2006 campaign, are seeking their first-ever girls’ basketball title.

“This is a team that hasn’t been in this situation, being able to hold on and finish things the last three or four years,” Portsmouth coach Tim Hopley said. “Tonight they found a way to do it and now we get to practice No. 60. That’s what we talked about the second we ended (the quarterfinal win) at Bedford. We wanted to get to No. 60. That’s tomorrow and I can’t wait to get there.”

Pinkerton trailed by as many as seven in the third quarter before a 9-0 run got the Astros a brief 25-23 lead. The Clippers (16-5) and Astros (18-2) within no more than five points of each other through the entire fourth quarter, where Pinkerton on two occasions in the final two minutes hit 1 of 2 free throws and then scored points after retaining possession following the missing the second freebie.

Jesse Ames gave Pinkerton a 3-point lead with three free throws in the final minute, but Graham had the response in the nick of time. The senior knocked down the tying bucket on a clean, no-hesitation look as time ran down, leaving Pinkerton without a chance to respond before overtime.

“A couple years ago, she was up here as a sophomore and went something like 0-for-8 in the (Division II) semifinals. It absolutely devastated her for a long, long time,” Hopley said. “For her to hit a shot to send us to overtime, the emotion just kind of came out of her and everyone after finally making a shot here.”

Laurence finished with a team-high 13 points for Portsmouth, which got nine from Hebert, eight from Reilly Velez, and six from Graham. Kane posted a game-high 17 points for Pinkerton while Mahoney posted nine points. Pinkerton got just four points from its reserves while Portsmouth picked up 12.

The Astros opted to steer clear of 6-foot-1 Laurence and Portsmouth’s other tall forwards for much of the game. The strategy backfired early as the Astros went 1-for-11 from 3-point range in the first half and 4-for-19 for the game.

Laurence and Hebert both had four fouls during the final two minutes of regulation and overtime, but Pinkerton did not try to take advantage and foul Portsmouth’s top players out of the game.

“There’s not one moment that loses this game. It’s not their 3-pointer, our foul shots or anything,” Pinkerton coach Lani Buskey said. “I’m cool with the way we ran our offense (in overtime). It’s a risk you take if you try to drive it too much because then you’re not going to get the clean looks on the outside.

“Hindsight is 20/20. There’s a few things I’d like to change if I’m being honest with you. … No regrets though. I think my girls played hard.”