The Great Valley High School field hockey standout had already wiped out twice on the slippery field at Octorara in the Southern Chester County League title game against National Division champion Oxford Wednesday on chances that saw her streaking up the field toward the goal.
Both of the spills could have led to Patriots scores.
But thankfully for her, she had one final chance to atone for those near misses. In the overtime period - that saw both teams enter deadlocked without a goal - Mosenson found daylight after the defense deflected an Oxford rush.
She streaked in on the right-hand side and was able to fire in a shot that beat Hornets' goalie Katie Fraver with 7:39 remaining in the 15-minute session to give the American Division champ Patriots (13-2 overall) the 1-0 victory in a hotly-contested game that was played in conditions that felt more suited for the kind of hockey on a icy surface.
Luckily for Mosenson, she got the shot off, because true to the game's form, she found herself on the ground after slipping while her teammates stormed the field.
"We had so many scoring chances throughout the game, I was just lucky that I made that one because I was very upset with myself for missing the others," said Mosenson.
The game was a far cry from the first time the teams squared off - a 5-1 Patriots thrashing on Sept. 23 that saw both teams enter the game with unblemished league records. In that one, Mosenson also was the offensive standout, scoring two goals and adding two assists.
The Hornets (10-6 overall), who wrapped up their trip to the title game with a victory over Garnet Valley on Monday, were able to frustrate the Patriots high-powered offense, continuously forcing them to take difficult shots and breaking up plays inside the scoring circle.
But the Hornets could not turn that defensive effort into offensive scoring opportunities, except for a few pushes down the field during the course of regulation.
They did test Patriots goalie Ryan Wentz in the overtime, forcing her to make two tough saves, before Great Valley scored the winning goal.
But in the end, it was a little of that "Mosenson Magic" as head coach Joe Tornetta called it that was the difference for the Patriots.
The win gave the Patriots their second SCCL championship, with the first coming in 1979.
The team hopes it is a sign of things to come as that squad went on to win the state championship under coach Rosemarie Trumbo.
"Our goal coming into the season was to win the league and we thought we had an opportunity to do that. We knew we had to play well and play together to do that. They kept within themselves doing that," said Tornetta, whose team should have one of the top seeds in the District 1, Class AAA playoffs.
"Even though things today weren't going well for us and we weren't putting the ball in the cage, we kept working and persevering and got the job done."
It was the third consecutive title game appearance for the Hornets since the SCCL split into the two-division format for the 2002 season. In those previous trips, they were defeated by Unionville.
This time around, the Hornets had to deal with replacing on of the program's top performers in Jaclyn Kulesza and incorporating several younger players into the rotation.
But as the season progressed, the team kept on improving and as a result will be a tough team to eliminate in their first season back in District 1, Class AA classification.
"We've had a really good finish to our season. They are really playing up heading into districts, which is good, because I think we will be one of the better seeds in the district," said Oxford coach Sue Townsend. "I was really proud of the way we played today."