The Man who became a machine versus the Machine who wants to be a man. Data's mind can not be affect by the force so Vader's
use of the Force is restricted to telekenesis. Throwing stuff at Data doesn't work since Data is fast enough to catch or dodge
whatever. Data will be allowed to have a phaser but it will be useless against Vader's light sabre. Vader would just block
any phaser fire with his light sabre, either just blocking or doing that cool move where he deflects it back to the shooter whereby
Data will take a hit. Vader can take the phaser away from Data with the Force, leaving Data to use hand to hand tactics. Data
is fast enough to dodge the light sabre so that won't work. The fight ends with Vader picking up Data using the Force and crushing his body, all in mid-air.
What is Data supposed to do if he is hanging in the air? By crushing Data's head or torso, Vader would disrut some systems which would turn Data off. Effectively killing Data.