Davis' pin-point pass freed Clark to go in on goal alone and he easily slotted the ball past Dallas netminder Kevin Hartman, enabling the Dynamo to grab a point and improve to 7-3-7 all-time against their Texas rivals.
Cam Weaver also scored for Houston to forge a 1-1 tie in the 42nd minute (3-4-6).
Andrew Jacobson collected his first MLS goal in the 27th minute and defender Ugo Ihemelu added a marker in the 70th for Dallas (6-3-4), which stretched its unbeaten streak to eight games.
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