Allenby's 4-iron shot on the par-3, 226-yard hole propelled him to 1 under and into a seven-way tie for sixth place on the inward nine at Oak Hill Country Club.
Nick Faldo, Scott Hoch and David Toms each had holes in one at the PGA Championship two years ago.
Allenby had the 32nd ace at the tournament since 1970 -- statistics before that year are incomplete.
Allenby, a four-time winner since joining the PGA Tour in 1999, has two fourth-place finishes this season, at the Sony Open and The Players Championship, and ranks 25th in season earnings with $1.4 million.
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