Sent off at odds of 22-1, Cajun Beat rolled home in 1:07.95 for the six furlongs, just 1/5 of a second off the Breeders' Cup record.
Bluesthestandard rallied up the rail in the final sixteenth of a mile to snatch second. Shake You Down, who had won six of his last seven races, faded in the late going but held third.
Zavata and Shake You Down led the 13-horse field through a hot first quarter mile in 21.02 seconds and Shake You Down ran a half mile in 43.32 seconds before Cajun Beat came along to wrest away the lead.
Cajun Beat has won four of nine starts this year for Kentucky-based trainer Steve Margolis.
Cajun Beat paid $47.60, $19.80 and $11.20; Bluesthestandard $12.60 and $8; Shake You Down $5.
The $2 exacta returned $380.10.
Swim Week Miami Beach 2014 [PHOTOS]