It is one of the most famous holes in golf because of an "island green" (it is actually a peninsula) that is surrounded by unforgiving water.
Countless balls will have been lost in that water through the years and for those that carry over to the island, there is also a bunker and merciless slopes to contend with.
But Moore avoided the hazards, attacked the flag, and scratched the number one into his scorecard the ninth ace in The Players Championship tournament history, and the first since Sergio Garcia's hole-in-one in 2017.
Watch Moore's incredible shot right here:
Here's the flight of the ball:
The eagle meant Moore, who was two under at the time, went four under which is the score he finished with having parred the 18th.
Moore is three shots behind current tournament leader Tommy Fleetwood, as the Englishman finished seven under for the day. Other notable scores include 5th placed Rory McIlroy who is five under and the American golfer Dustin Johnson who is 12th with a first day score of -3.
The second round takes place on Friday, ahead of the third round on Saturday, and final round on Sunday.
The winner scoops a $2.25 million payday.