It couldn’t have been set up any nicer for the Lady Dragons.

A Hingham win over top seeded Martha’s Vineyard and Norwell’s win over third-seeded Mansfield had Duxbury in the perfect position to advance for a shot at its second MIAA Division II lacrosse title.

Having beaten Hingham and Norwell during the regular season was surely a good sign for Coach Sue Paull’s team, as they entered the semifinals on Tuesday at Pembroke High School to take on Norwell; an 18-13 Duxbury victim earlier in the year.

If Paull had any fears during the regular season it was the ability of her defense to limit the number of shots on goalie Stephanie Hoomis. Averaging close to 17 goals a game, the Lady Dragon defense got the job done by limiting opponents to seven through the first 20 games.

What took place on Tuesday makes all those comparison pointless, as Norwell beat the Lady Dragons in every phase of the game and moves on to the South Sectional finals against fourth seed Hopkinton after crushing Duxbury, 18-16.

While the final score made the game look close, anyone in attendance would agree the Lady Dragons collapsed under the pressure.

Falling behind early, Duxbury crawled back to take a 3-2 lead on a Siobhan McCarthy goal with 17:22 left in the half. Goals by Caitlin Burke, Katie Griffin, and Meg Muncey would put the Lady Dragons up 6-3 just five minutes later and things were looking good.

Hoomis made a big save on a Norwell start-up with 11:40 on the clock, and goals by Muncey and Griffin kept the three-goal margin intact with 7:11 remaining and Duxbury in charge, 8-5, with Paull calling a timeout.

When the timeout was over, it was like David Copperfield had made the Lady Dragons disappear. The Clippers took over and scored at will, as junior Olivia Huie scored three goals and Lexi Demarco added another to give Norwell the lead for good at 9-8 at halftime.

With plenty if time left in the game Duxbury needed to regroup and get back to what made it 17-1 during the regular season.

What Paull got instead was a complete defensive breakdown, as Norwell’s Kate MacDonald (3) and Molly Cox (2) led a ferocious assault on Hoomis that produced a 6-1 run for a 15-9 lead with 13 minutes left in the game.

McCarthy and Muncey scored nine seconds apart to cut the deficit to 15-11, but after Demarco beat Hoomis, Paull sent in freshman Haley Schmerhorn to man the net.

MacDonald continued to torch Duxbury and made it 17-11 with 8:51 to go, sending a clear signal to the Lady Dragons that the Clippers would continue to be a thorn in their side.

Muncey (2) and Burke responded to cut the margin to 17-14 with 4:09 to go, but Cox was left all alone and beat Schmerhorn to make it 18-14 with 3:20 remaining.

Goals by Muncey and McCarthy kept Duxbury’s hopes alive and made it 18-16 with a minute left in the game, but the comeback died with 45 seconds to go when Griffin worked her way inside and fired wide on goalie Justine Sullivan as the Clippers gained possession and ran out the clock.

“They were the better team today. No doubt about it,” said a disappointed Paull. “The turnovers just killed us and we couldn’t win many draws in the second half.”

The Yale-bound Muncey, who was the team MVP this year, led the way for Duxbury with seven goals, while McCarthy (3), Burke (3), Griffin (2), and Mimi Smith rounded out the scoring.

The loss also ended the high school lacrosse careers of seniors: Hoomis, Melissa Crimmins, Liz Desmond, Alexa Matthews, Lauren Schneiderhan, and Muncey.