The Blues had comfortably beaten Villa in the group stage but Montpelier made the better start and were 1-0 up inside five minutes.
Rustington rallied and levelled on 15 minutes.
Gary Peters clipped a ball down the line on the right hand side for Chris Darwin who ran behind the defence to lob the ball over the stranded Villa goalkeeper.
Villa stepped it up and went in 3-1 at the break with two goals, the first a lob over Billy Nash from a straight long ball and the second a penalty converted after a Peters foul.
Despite their best efforts after the break to get back into it, Villa extended the scoring in quick fire succession and ended the game as a contest on the hour mark, both from corners.
The first was a scrappy finish from a header inside the six-yard box and the second a curled effort from 18 yards after the Blues failed to clear the initial corner which made it 5-1.
With the game fizzling out, Dec Jenkins appeared to have scored a second Rustington consolation only for the officials to have deemed the whole ball didn’t cross the line.
In injury time, Carl Bennett was dismissed for kicking out with a Villa player which ended a not so triumphant night for Jon Tucker’s men.
Rustington: Nash, Peters, Miles, MacIver, Gilchrist, Oliver, Brown, Butt, Jenkins, Irish, Darwin. Subs: Crouch, Cleall, J Bennett, C Bennett, Chick.