Bjerregaard used a six-iron from 206 yards, and his ball never deviated from the flag, taking one hop and then disappearing on the second bounce at Bethpage Black.
Suitably impressed, his playing companion Lucas Glover, the 2009 U.S. Open champion here, also got in on the act by holing a 50-foot bunker shot for birdie at the hole.
The ace helped Bjerregaard to a round of three-over-par 73 as he closed out his PGA Championship debut in style.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
He finished at three-over 283.
Bjerregaard is a twice European Tour winner but the 27-year-old's claim to fame in his still young career came when he beat Tiger Woods at the WGC-Match Play in Austin, Texas in March.
(Reporting by Andrew Both; editing by Ken Ferris)
