Byrd's ace in the fading daylight on the par-three 17th allowed him to best last year's winner Martin Laird and Cameron Percy in stunning fashion at TPC Summerlin in Las Vegas.
Byrd teed off first among the trio. His shot bounced hard and then rolled 10 feet directly into the cup. Due to the darkness, Byrd couldn't tell at first what had happened and so hardly reacted.
"I couldn't see it," Byrd told The Golf Channel. "I'm in shock. I think the people at the green were the only people who could see it. I hit it perfect. For it to go in, that's just luck."
After the ace, Laird and Percy still had to tee off even though they had no chance of matching Byrd's feat. Both plunked their shots into the water and Byrd sealed his fourth career PGA Tour victory and first since 2007.
Laird came up short in his bid to became the first back-to-back winner at Las Vegas since 1998-99 when Jim Furyk did the trick, while Australian rookie Percy posted his best-ever PGA Tour finish.