AP Racing Writer

LOUISVILLE, Ky. - No one knows Big Brown better than Michelle Nevin.

The exercise rider for the unbeaten Kentucky Derby favorite has ridden the big bay colt more than 100 times, and she remains awed by his graceful stride and powerful running style.

"The horse just floats over the ground," Nevin said in her Irish brogue following Big Brown's final workout before Saturday's Derby. "You don't feel like you're going that fast at all. He just lengthens his stride. It's very smooth. It's very comfortable. He's like a powerhouse underneath you."

Big Brown is all that, and more. The colt with three victories by a combined 29 lengths has created quite a backstretch buzz at Churchill Downs.

Dozens of photographers followed Big Brown to the track for Thursday morning's tuneup. Fans gawked at the striking colt, with one hollering, "There goes the Derby winner."

After breezing three furlongs in 35.40 seconds, Big Brown barely worked up a sweat and walked back to the barn with a bounce in his step.

Asked if she was concerned about any of the 19 other horses in the field, Nevin smiled.

"Not after that," she said.