For Eastern, Tom Flacco had another stellar game passing the ball, going 20 for 35 for 244 yards and three touchdowns.
"Our defense really stepped up at the end. Our offense needed to step on their throat at the end, and we didn't," Flacco said.
With 1 minute, 58 seconds remaining, Atlantic City took over at its own 24 down by the six points.
Prevard completed three passes for 52 yards and rushed once for 15, but fell short of the comeback when he was tackled by Wilcox.
"We'll take it - five turnovers and we win the game," Eastern coach Dan Spittal said.
Eastern will host Millville next week in the semifinals.
"We realized they were picked to lose the game," Flacco said of Atlantic City, "but you get in the playoffs in this division and you know everyone is a good team and everyone is going to be battling."
Atlantic City 14 6 6 0 – 26
Eastern 17 0 15 0 – 32
E: FG Todd Spirt 27
AC: Derrick Osh-Shakkur 76 kickoff return (kick blocked)
E: Tom Flacco 1 run (Spirt kick)
E: Jarrel Levicoff 43 pass from Flacco (Spirt kick)
AC: Osh-Shakkur 19 run (Isaiah Graves pass from Osh-Shakkur)
AC: Graves 13 pass from Jamir Prevard (run failed)
E: Cinque Hill 3 pass from Flacco (Spirt kick)
AC: Dennis White 76 with fumble (kick blocked)
E: Keshawn Segers 17 pass from Flacco (kick blocked)