The goal occurred moments after No. 4 Montoursville (13-6) committed a foul just outside the box.
"We always preach that the first thing as soon as there's a foul, just place the ball and hit it right away," said Dressler. "This time we were lucky enough that Montoursville was asleep and arguing (the call), and we just put the ball through clean."
Six minutes later Dempsey scored again, and this time he connected off a Gage Reber assist.
"That was pretty much the game-ender right there, because we had a two-goal lead and the momentum," said Dempsey.
With 8:46 left in the game the Ironmen completed their scoring when Derek Kirkner got in on the action by scoring off another assist by Reber.
"We've had a potent offense all year with Gage and (Eric). Gage has 19 goals on the season and now I think (those two goals) get Eric up to 16," said Dressler. "You have two guys scoring a lot of goals, so it makes it tough for the other team to just (zero) in on one guy."
Danville will need to keep on scoring when it faces Lewisburg, a 6-0 winner over Shikellamy, in Tuesday's semifinals at a site and time to be determined.
In each of the last two years, the Ironmen have lost to the Green Dragons in the semifinals.
"The last two years we faced Lewisburg in the semifinals, so we might as well make it three years in a row," said Dressler.