A method of preventing a pre-ignition event within a cylinder (20) of a spark ignition engine (100) involves taking in-cylinder measurements and using the measurements to determine the instantaneous heat being released within the cylinder (20) as a function crank angle. If significant heat is being released before the intended spark timing, additional fuel is injected into the cylinder (20) immediately following the detection of early heat release (pre-ignition) within the same engine cycle, preferably within 45 crank angle degrees following the detection of pre-ignition. The additional fuel quenches the heat released within the cylinder (20) to prevent a pre-ignition event.