Maclean struck in the 11th minute following a strong run into the area that resulted in the ball bouncing off the Saltdean ‘keeper and back to Maclean who did enough to see the ball go over the line.
A second goal soon followed from Ryan McBride after Wes Tate had seen his initial effort saved, but Tate reacted faster than anyone to lift the ball to McBride who slotted the ball home with ease.
Maclean plundered his second goal of the evening with barely twenty minutes played as his angled drive from 15 yards was too good for the home ‘keeper.
Tate attempted to extend United’s lead to four on the stroke of half-time but his swerving effort was well saved at the near post.
With the game effectively over as a contest, United looked comfortable in possession of the ball and solid all over, but Saltdean were given a route back into the game on 69 minutes.
Luke Denton was adjudged to have committed a foul in the penalty area that gave former United striker Ryan Walton the chance to reduce the deficit to which he duly obliged.
McBride put the tie beyond any doubt as he latched on to a perfectly weighted cross field ball from Scott Dartnall to lash a left footed effort past the stranded ‘keeper before Maclean completed his hat-trick and the scoring for the evening with a low effort that beat the ‘keeper at the near post.

The draw for the Second Round of the Sussex Senior Cup will be made on Thursday 31st October at 12:30pm