It’s only the rarest of hockey games that features three periods of up-and-down, high-scoring, roller-coaster action, and then continues with nearly a full game’s worth of scoreless, grind-it-out attrition.

But that’s exactly what the 1,013 in attendance at the

Bright Hockey Center on Saturday were privileged to witness as No. 4 Harvard (25-6-3) came from behind to best No. 6 Mercyhurst (28-7-2), 5-4, in triple overtime and advance to the NCAA Frozen Four this upcoming weekend.

After senior tri-captain Nicole Corriero erased several Laker leads with four goals in regulation, she delivered the dish to linemate Julie Chu on a 2-on-1 breakaway for the game-winning tally 12:28 into the third extra period.

“Our conditioning came in as a factor,” Corriero said. “And Julie was able to find that bit of energy and make a sick move, thank goodness.”

With the puck deep in the Harvard zone, freshman Sarah Vaillancourt received a pass and carried the puck across the Crimson’s own blue line before feeding a streaking Corriero on the right side. Corriero drove up the ice along the right boards and angled towards the net, forcing Mercyhurst goalie Desirae Clark to commit at the right post before crossing to Chu, who lifted a backhander over Clark into the net.

Chu leapt in the air in celebration following the goal. She was immediately mobbed by her joyous teammates and jubilantly applauded by the hearty Harvard fans that had sat through the longest game in NCAA tournament history and were rewarded with a thrilling victory that prolonged the Crimson’s national title hopes.

“We always say, ‘We’ve got lights on this pond,’” Chu said. “It was two games’ worth of hockey that people really battled out, and hats off to Mercyhurst and our team for being grinders.”

The Chu strike broke a stalemate that had lasted since Corriero tied the game just 38 seconds into the third period. On that goal, the second of the team’s two scores at 5-on-3, Corriero cleaned up the rebound from a Vaillancourt slapshot and tucked it past Clark to knot the contest at 4.

From that point on, the game evolved into a defensive struggle headlined by the record-setting performances of the two goalies.

Clark, a senior, posted historic numbers in her final collegiate appearance, with a national single-game record 78 saves, including a number of acrobatic stops on the sporadic Harvard flurries that spotted the overtime periods.

“I doubt if I’ve seen a better goaltending effort this year,” Harvard coach Katey Stone said. “Or in many years.”

While Clark gave her team a chance to win, Crimson junior netminder Ali Boe rebounded from a shaky opening frame to stonewall the Lakers attack, posting 77:08 of shutout hockey down the stretch and her second-straight career-high in saves, racking up 56.

“She bounced back and she was tremendous the rest of the way,” Stone said. “She came up with some huge saves.”

Together, the duo saw 143 shots on goal, shattering the previous record from the 2003 NCAA final. Harvard’s 83 total shots and 21 in the second period were both team highs.