The Hawks won the 130-127 bout on Wednesday at McCamish Pavilion on the Georgia Tech campus.
Atlanta and San Antonio were tied at 127-127 with about six seconds remaining when Young dribbled near half court with Spurs guard Bryn Forbes defending. The former Oklahoma Sooners star eyed Forbes before eventually picking up his dribble and launching a prayer from the Georgia Tech logo, well beyond the 3-point line.
Young sank the straightaway look from about 30 feet, leaving the Spurs just seconds on the lock.
"I knew we were tied so I just wanted to make sure it was the last shot," Young told reporters. "So if I made it, it was good and if I missed it we were going to overtime. I just wanted to make sure it was the last shot that we could really put up."
Young said he would have passed the ball if anyone else was open during the sequence.
The Hawks phenom made a habit of attempting similar deep looks in college, en route to averaging 27.4 points per game in his lone season for the Sooners. He jacked up the fourth-most 3-point attempts in the NCAA, yet averaged the fifth-best 3-point percentage in the Big 12.
The No. 5 overall pick in the 2018 NBA Draft scored 22 points and had seven assists, three rebounds and two steals in Wednesday's win. Spurs forward Rudy Gay scored a game-high 28 points in the loss.
Atlanta battles the Heat in its final preseason game at 8 p.m. on Friday at AmericanAirlines Arena in Miami. The Spurs face the Magic in their final preseason clash at 7 p.m. on Friday at the Amway Center in Orlando.