When two offensive players couldn't seem to score against just one defender, Chadwin took notice.
"What are you guys doing, having a party?" he said. "Finish it!"
When another player made an errant pass that led to a turnover, Chadwin pulled him aside.
"You're smarter than that," he said. When the teen attempted to explain why the turnover occurred, Chadwin cut him off.
"Don't talk to me about it. Show me!" he challenged.
After so many years of coaching, Chadwin, 62 and Jewish, has learned the importance of treating each player individually.
"Some kids might need a hug, or I might have to get into some player's face and be a little more stern with them," said Chadwin, affectionately called "Coach C" by his players. "You coach their personalities and see how they respond to you."
Just two days later -- on Jan. 18 -- the team was back in that same gym for a game against LEAP Academy University Charter School, and its 87-53 victory marked Chadwin's 500th win.
Chadwin himself was a successful high school player at Germantown High School, and then spent a year playing for East Tennessee State University, where he eventually earned a health and physical-education degree.
From there, he coached at Germantown Academy before taking the reigns of AFS in 1978. In his first year at the new prep school, the team won only eight out of 22 games, but Chadwin believed that he might just have something to build on.
"There were a lot of kids who wanted to be coached and wanted to have a successful program," he said. "They just needed somebody who had a plan, and knew how to coach and showed a lot of enthusiasm."
Pretty soon, the team grew competitive, but it took till 1986-87 for Chadwin to win his first Friends League Championship. From there, AFS went on a roll, winning eight straight league championships from 1990 to 1997.
Currently, he has just 198 losses against his 500 wins, and has won 15 league titles.
He admits that early on in his career, his main focus was to win games, but that soon changed.
"The emphasis shifted basically to helping kids get into college, making sure they were good people, making sure that when they graduated, they touched other people's lives and gave back to them," relayed the coach.
While basketball season only lasts a few months during the winter, Chadwin has instilled a program that can keep kids playing all year -- whether it's fall workouts, springtime leagues, or taking part in camps or outside leagues in the summer.
Before the current season began, he considered his squad to be "young and inexperienced," and said that he was unsure if this year would be a success.
Currently, the team is 13-5, and has seen winning streaks of five and six games.
"I think we're getting better each game. Our defense has really improved, and I think that's what carries us," said the coach. "We learned early on how to win close games. We've had about seven or eight close games. Kids stepped up and made plays at critical times to win ball games."
Even after so many overall wins, Chadwin said that he stays focused on learning, calling himself a "student of the game."
"I still go to clinics. I watch tapes. I watch tons of college games. I'm always trying to get better and pass it on to the team."
After reaching his recent milestone, the team presented Chadwin with an autographed ball, and school officials made a presentation in his honor. While Chadwin said that he was happy his win could bring the school some recognition, he's just not sure what all the fuss is about.
"It's a relief, it's over with, let's move on to the next game. I'm just a basketball coach."