The No. 3 ranked Bulldogs missed a 42-yard field goal as time expired in Athens, Georgia, handing the Gamecocks their biggest upset win since they knocked off No.1 ranked Alabama in 2010.
It's the first time a top-6 team in the Coaches Poll has lost this year.
It was South Carolina's first win over a ranked opponent in three years and the first time an SEC team was defeated by an unranked team this season, according to USA Today.
The Gamecocks won despite being limited to their third-string quarterback, Dakereon Joyner, who entered the game after starter Ryan Hilinski was injured in the third quarter.
Hilinski wore the No. 3 jersey to honor his brother Tyler who committed suicide on January 16, 2018.
Georgia QB Jake Fromm turned the ball over four times, while kicker Rodrigo Blankenship missed a kick in double overtime to give the victory to South Carolina. Gamecocks kicker Parker White had connected on a 24-yard field goal earlier in the second overtime to give South Carolina a three-point lead.
South Carolina head coach, Will Muschamp said the Gamecocks have been resilient in dealing with adversity so far this season.
"It was Jake [Bentley] early in the season, we lose Ryan, Dekereon [Joyner] was halfway practicing because of his hamstring," South Carolina coach Will Muschamp told ESPN after the game. "It says a lot about the culture of our program, the leadership in our program, the players in our program and the future of our program."
The loss hurts Georgia's postseason aspirations as they must win out to have a chance at making the College Football Playoff.