Scott Garlick made on save on two shots on goal for RSL (9-12-6), which is fourth in the Western Conference with 33 points to 46 points to West front-runner FC Dallas.
Freddy Adu scored an un-assisted goal in the 45th minute; and Nick Rimando made two saves on three RSL shots in his first match of the year for United (14-3-9), which leads the Eastern Conference with 51 points to 38 points for second-place Chicago.
With the draw, RSL assured it would not lose to United this season after a 2-1 win at Salt Lake City in July.
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