Trailing 1-0 for most of the game, Philadelphia pulled even when Gomez intercepted a pass from Dallas' Carlos Rodriguez and headed it into the bottom-left corner.
Philadelphia (2-6-2) has not won since April 21 when it beat Chivas USA.
Blas Perez scored in the 7th minute for Dallas (3-6-4), which last tasted victory April 14 with a win over Montreal.
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