Presbyterian (4-9) won for the first time in the series between the two schools. It was their ninth meeting over 53 years.
Appalachian State (2-8) scored the first 10 points of the game and jumped out to a 14-2 lead. But the Blue Hose came right back, using a 15-4 run -- punctuated by 3-pointers from Downing and Reggie Dillard -- to take the lead at 20-18 en route to a two-point halftime lead at 39-37.
The Mountaineers took the lead at 49-47 at 14:25 of the second half after a 7-0 run, but Presbyterian was resilient as Truss made a pair of free throws, followed by a Downing trey, to retake the lead at 53-50 and it never trailed again.
Appalachian State was led by Tab Hamilton with 33 points.