Unpublished (4), at 4-1, beat the 2-5 favorite Company Store (5) by a length after a stretch-long duel in Friday's third race at the Gulfstream Park West meet.
Ir was the first leg of the Rainbow 6, with a carryover of $275,169.
Bettors added $103,304 to the Rainbow 6 pool.
The race was six furlongs on dirt for maiden claimers. Aldemar Santos rode Unpublished for trainer Gary Jackson.
Conditions are listed as Fast and Firm and there is only a 15 percent chance of rain during the remainder of the eight-race card.