Work rider Carlos Rosas says the surface at Santa Anita won't hamper Curlin on Saturday.
Steve Asmussen's charge is the 7-5 morning line favourite for the Breeders' Cup Classic at Santa Anita.
Many judges believe the only question mark about his chances concerns the synthetic Pro-Ride surface there.
But after partnering Curlin in work on the track on Thursday morning, Rosas said: "He's a superstar. He's getting over the ground here very well. I know there's a big difference between the mornings and afternoons, but he's showing us very good signs. I don't think the surface (Pro-Ride) is going to be a problem at all."
Trainer Asmussen, while pleased with Curlin's training all week, sounded a note of caution when he said: "The synthetic track is the question."
"Right now we're very happy with what he's done so far," added Asmussen. "I'm very excited for the opportunity to run him in the Classic again."