The fire occurred Saturday during a test session for the Feb. 5-6 Rolex 24 Hours At Daytona.
Newman's rear-engined Crawford DP03 Daytona Prototype had just left the 2.5-mile tri-oval -- where the cars approach their 190 mph top speed -- and spun out, the Daytona (Fla.) News-Journal reported Sunday.
Newman, 79, missed steel barriers bordering the turn and attempted to resume his run when he saw the car's rear engine was on fire. He released an in-car fire extinguisher and climbed out of the vehicle.
"I'm fine and we'll return with a healthy car to race in the Rolex 24," Newman said. "It's just racing luck. That's all."
Newman's crew said the fire was caused by a failure of the fuel pump diaphragm gasket.