NEWTON, Mass. — This game was billed as an instant classic worthy of being played on championship weekend. It lived up the lofty expectations.

And then some.

Dempsey Arsenault’s falling goal in front of the crease off a feed from Sam Apuzzo with 1:42 left in overtime sent fourth-seeded Boston College into the NCAA women’s lacrosse semifinals with a 12-11 win over visiting Stony Brook, the fifth seed, Saturday afternoon in front of 816 fans in a constant rain.

After an intensely emotional 64-plus minutes featuring four stick checks, six yellow cards and two green cards, Tewaaraton finalist Sam Apuzzo provided some clarity.

“I think this was a great game, could’ve been the national championship,” she said. “Both teams played like it was. I think it was just a great game for everyone to watch, just to see the talent on both sides.”

It was a contest of runs, with Boston College (21-1) establishing itself early by winning the first three draws and subsequently taking a 3-0 lead. The Eagles led 5-2 before Tiffany Zullo put the exclamation point on a 4-0 run on a free position goal that just beat the shot clock. Ally Kennedy would give Stony Brook a 7-6 lead entering halftime.

With the score tied at 8, Stony Brook (20-1), the No. 1 team in the national polls since Feb. 26, went on a 3-0 run for an 11-8 lead. Kennedy, who shined with five goals on a day when Kylie Ohlmiller (two goals, three assists) and Courtney Murphy (two goals, one assist) were keyed on by the defense, scored twice during that run.

But Apuzzo’s excellence on the draw carried Boston College the rest of regulation. She had seven of Boston College’s 20 draw controls, outdrawing Stony Brook’s six draws all by herself. Boston College tied the score at 11, effectively forcing overtime, when Apuzzo fed Tess Chandler.

“Stony Brook’s really good [defensively],” Apuzzo said. “They like to bait people to pass into the middle and just pick them off. We were just smart and patient, making sure we were making the right passes around the circle.”

Ohlmiller attempted a difficult shot with mere seconds remaining in regulation, but Lauren Daly made the save to force overtime. Ohilmiller was faceguarded primarily by junior Elizabeth Miller, who helped stymie the Tewaaraton candidate.

And without Taryn Ohlmiller, who coach Joe Spallina announced after the game had torn her ACL in the 18-5 win over Penn last week, the Stony Brook offense struggled to feed in the same way it did all season.

“I can open up now, Taryn Ohlmiller has a torn ACL,” Spallina said. “She’ll be going in for surgery in a week. We lost a 100-point scorer, so we kept it under wraps, but that hurts in a game like this. It’s your playmaker. It disjointed us on our man-up, our power play. She’s the real deal.”

Spallina praised his senior class, featuring record-breakers like Kylie Ohlmiller and Courtney Murphy, as well as All-American Brooke Gubitosi and do-it-all midfielder Samantha DiSalvo. It’s them, he said, who helped lift the program to national recognition.

“What they’ve done is larger than life in the sense that there’s not many sports that just have a bunch of kids that have taken the sport over,” he said. “Maybe they didn’t come in as top-100 kids but they’re leaving as some of the top kids to walk the planet in the sport. Their legacy won’t be decided on the fact that they’re not playing next weekend.”

It’s Boston College that will play top-seeded Maryland on Friday in the semifinals at Stony Brook’s LaValle Stadium, with the winner playing in the championship against the winner of No. 2 North Carolina and No. 3 James Madison on Sunday at noon.

With uncertainty around the team following Kenzie Kent’s decision to focus on hockey rather than lacrosse this season, Boston College’s quartet of Apuzzo, Chandler, Arsenault and Kaileen Hart have done much of the heavy lifting. It’s that depth that makes the Eagles a real threat against Maryland, which won the national title over BC last season.

“It’s an amazing feeling,” said Apuzzo, who is from West Babylon, roughly 30 miles from LaValle Stadium. “I think coming into this season, we weren’t sure what was going to happen with the year. But preseason and the early season, we worked so hard for this. I think all the hard work that we’ve done is just paying off in this moment, which is so exciting. I’m excited to go back to Long Island.”

Friday’s semifinals might not top Saturday’s action, a game that had a championship feel and the intensity you’d expect from a top-notch matchup.

It lived up to the hype.