Mediate, with one victory on the Champions Tour since becoming eligible for the circuit last December, went birdie, eagle, par, birdie, eagle on the closing stretch at the Canyon Meadows Golf and Country Club.
John Riegger, whose first Champions Tour victory came a week ago in Seattle, shot a 69.
Mediate's lone triumph on the over-50 circuit came in the opening event of the year -- The Allianz Championship. He has had four Top 10 finishes since then, including a tie for third at the U.S. Senior Open.
Notable deaths of 2014 [PHOTOS]
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