Ahu is embellished by horse accessories and was powder blue leather over grey upholstery fabric.
"I like to use things that aren't generic, that look a bit different," Ms Whitewood said.
The pair were thrilled with their prizes which included Novotel packages and entry into Prix de Fashion at Ellerslie.
TRAC marketing and sponsorship manager Don Patterson said thousands of people turned out to Arawa Park on Saturday to enjoy the glamour and excitement of race day.
He said it was perfect "Goldilock's weather" which accounted for the full stands and front lawn.
"It was not too hot and not too cold."
Mr Patterson said he was pleased with the quality of entries in the Fashions in the Field competition.
"[It's] always hard as Rotorua is one of the first fashion competitions in the season and often the outfits were not assembled."
He said last year's Fashions in The Field winner, Claudia Campbell, went on to win Prix de Fashion at Ellerslie.
Mr Patterson said the racing also went well, with lots of close finishes.