A FIRE that burnt five hectares of grassland south-west of Ballarat is believed to have been deliberately lit.The fire took hold on private property bordering the Linton State Forest at Happy Valley shortly after 1pm.CLICK HERE to see more pictures from the fireIt quickly spread despite a lack of wind, burning five hectares of grassland in almost three hours.No homes or livestock were threatened by the fire. Police and fire investigators said the fire was suspicious.A Vicfire spokesman said eight fire crews worked to bring the fire under control.Aircraft and dozers were also involved in the fire fight, he said.Blacking out would be carried out this afternoon, he said.