Streelman's effort was the low round of the day on the Copperhead Course at Innisbrook Resort and Golf Club.
It enabled him to finish 54 holes at 6-under-par 207, knotted atop the leaderboard with Leonard (67) and Coetzee (68).
First- and second-round leader Shawn Stefani, meanwhile, tumbled into a five-way tie for eighth place at 4-under 209 with a disappointing round of 3-over 74.
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