A lightsaber takes time to cut through metal. It would not be able to cut Superman.
Luke's reflexes are fast for a human, but Superman can react at a good percentage of the speed of light. If Luke tried to use the Force, Superman could fry Luke with a wide beam blast of heat vision or freeze him with cold breath, or just slap his hands together and turn Luke to jelly with the shock wave. Or just keep it simple and pound his fist through Luke's chest in a millionth of a second.
The Force is a nice trick, but I have not seen it able to completely prevent someone from moving. Heck, Superman could even flick a booger through Luke's skull if his hand was the only thing he could move.
People like to throw in kryptonite or red solar radiation. Sorry, but that is not Luke's abilities beating Superman.
Luke could not even dream of being in the same class as Superman.