The Earthquakes, desperate for points to keep their playoff hopes alive, jumped in front of RSL on Lenhart's first goal in the 18th minute.
Lenhart got what turned out to be the game-winner in the 21st minute when midfielder Shea Salinas placed a free kick into the box where Lenhart headed it past RSL goalkeeper Nick Rimando.
The victory gave the Earthquakes 41 points, while Real Salt Lake stayed stuck on 48 points.
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