Ortiz scored the last six points of regulation for Wagner (5-5) and made a steal with three seconds left to send the game into overtime.
Mario Moody hit two free throws early in the extra period, and Jay Harris buried a 3-pointer with 1:57 left to give Wagner a 67-62 lead. Ortiz hit two free throws with 36 seconds left to make it 69-62.
Wagner hit 6 of 8 free throws in the final 20 seconds to ice the game.
Fran Dougherty scored 17 points and pulled down 11 rebounds to lead Penn.