El Salvador's Jaime Alas blasted a shot from some 25 yards out with about oneminuteleft in the match, and the ball bounced off the hands of goalkeeper Sean Johnson before darting into the goal.
Rafael, who had replaced Neville in the 63rd minute, pulled one back in the final minute with a spectacular left-foot volley from the edge of the box after Arsenal failed to clear a Giggs cross.
Newcastle were pushing hard for the try that would have won them the game at the death, and some of their players were incensed when referee John Paul Doyle blew for full-time with oneminute and eight seconds still left on the scoreboard at Kingston Park.