Arnaud got the equalizer directly off a free kick. He took the shot from outside the left edge of the penalty area and drove it over traffic and past Union goalie Chris Seitz into the upper-right corner.
The Wizards (7-9-6) moved to 2-1-2 in their last five road matches and 4-1-3 in their last eight overall.
Philadelphia (5-11-6) got a first-half goal from Sebastien Le Toux.
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