Blake has won just once on the regular PGA Tour and has yet to win on the over-50 circuit. His best finish on the Champions Tour came at last year's U.S. Senior Open.
Defending champion Bernhard Langer shot a 68 and was tied for 14th place. Langer holed out from a bunker for an eagle during a playoff last year to defeat John Cook.
Cook shot a 71 Friday, bringing an end to a streak of 12 straight rounds in the 60s.
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