A bird brought new meaning to "deuce" at a tennis competition in Australia this week ... by crapping all over Reilly Opelka during a match!!
It all went down at the Melbourne Summer Set ... when a bird decided to do its business right on the (ironically enough) #2 seed's hat during the second set against Maxime Cressy.
Opelka -- the #26 player in the world -- was immediately ticked off by becoming a human toilet ... walking over to the chair umpire in hopes of switching out his hat.