Joyner is now 100-97 in six-plus seasons.
American led 23-21 at the break but Pressley drove for a layup, then nailed a jumper to start an 11-4 run to open the second half and Hampton took a 39-27 lead. Jesse Reed made two free throws and a layup as American closed to 50-46 with 1:12 left. Johnson made a 3-point play for a 53-46 lead.
The Pirates shot just 36 percent the first half but finished with 23 of 49 (46.9%) from the floor.
Paris Maragkos and Reed had 12 apiece to lead American (0-2).