Northern Ireland were harshly beaten 5-3 by Spain at Shamrock Park on Thursday night
Crusaders' Gavin Whyte, who would later hobble off injured, had done well to win the penalty, hacked down senselessly as he tried to shepherd the ball out for a corner.
Oyarzabal thought he had given the visitors the half-time lead with another cool finish on 44 but Donnelly struck again in injury-time, lashing home, even if Shayne Lavery did try to steal it as it went over the line.
Spain started the second half in perfect fashion, Real Madrid's Borja Mayoral converting his first of the night, this one an audacious flick into the bottom corner.
Mayoral would go on to completed a hat-trick with another two close-range efforts but not before NI levelled at 3-3.
This goal came from Everton's Shayne Lavery, a smart touch and blasted finish profiting from fearless running by Glenavon's Mark Sykes, who skipped past a couple of Spain's La Liga defenders.