The gamewinner came with just under four minutes remaining in the first overtime when Emily Redberg fed Rossi on the left side of the box where she struck the ball, putting it into the right corner of the net for her second of the season.
"I was struggling during the first part of the season and the team's been so supportive," Rossi said. "It feels so good to just get that goal."
The Gamecocks used their quickness to get back into the game in the second half. Darcel Mollon and Ashley Kirk scored to erase Tennessee's 10 advantage on Mick Imgram's first-half goal.