The Millers are currently sitting in the final play-off position, five points clear of Heybridge Swifts who have just one game remaining after losing 2-1 to Grays Athletic last night.
That result means that the Millers cannot be caught with two games left of the regular season.
Aveley will have to wait though to discover who they face in next week's semi-final, although we do know that it will be away to either Maldon & Tiptree or Thamesmead Town.
Results in the final two games of the season, starting tonight against Waltham Abbey at Mill Field and then Soham Town Rangers on Saturday, will determine who out of Aveley and Witham finishes the higher with the team finishing second playing host to the team in fifth and the team finishing in third playing host to the team in fourth.
Whether it's Maldon or Thamesmead, it is guaranteed to be a difficult encounter with the Millers being unable to secure a win against either side in their five previous meetings this season. Although in those matches Aveley have only lost once, drawing the other four, with their solitary defeat being a last minute 3-2 loss away at Thamesmead on New Years Day.
Congratulations to all the staff and players at Mill Field for a fantastic achievement.