The Leopards built a 1-0 lead nine minutes into the game, as Smith caught the left corner of the goal on a 25-yard, floating free kick from the right side.
"I just chipped it over everybody," said Smith. "That was my fourth goal like that this season."
The senior midfielder then knocked home the game-winner.
With the Leopards on the move with just over six minutes remaining in a 1-1 tie, Gaels keeper Margot Weneck drew a penalty for tripping Smithsburg's Kristen Poffenberger in front of the goal. Smith got the shot duty, and drilled a low line-drive into the left corner of the net, just past a diving Weneck.
"You look one way," Smith said, "and knock it another."
In between the Smith scores, the teams battled through the puddles for possession, slipping and sliding through several would-be chances.
"This was my first game in these kinds of conditions," said Goretti head coach Mike Bowers. "The field got progressively worse as the game went on."
But, with the Leopards attack rather neutralized, the weather also set the potential scene for an upset.
With just over 20 minutes to play, the Gaels (1-9) knotted the game at 1, as Katie Chambers' direct kick from the top of the box slipped through the hands of Smithsburg keeper Lisa Belella for a goal.
"Days like this," Fowkes said, "the mistakes end up as goals."
Goretti rode the newfound momentum for as long it could, which, as has been the case for the Gaels all season, wasn't quite long enough.
"We've lost seven games by one goal this year," said Bowers. "We've been in every game. We're just a little short, but the kids are starting to come together."
The Leopards outshot the Gaels, 26-13, while Weneck registered 17 saves and Belella made 5.
"It was pretty sloppy," said Smith. "We could have played better, but what can you say in this weather?"