The Algerian side becomes the first team to qualify for the semis of the 2015 Orange CAF Champions League following their fourth straight win at the group stage.
With a 2-1 win from the previous fixture a fortnight ago, USMA confirmed their place with back-to-back victories against the whipping side of the group.
It is the first time since 2003 that the Algiers based side have reached the last four of the premier continental club championship and they achieved the feat in a superb fashion this time with a 100 per cent record after four matches at the group stage.
Eulma, who will play in the second-tier of Algerian football next season have yet to recover from their poor start, sinking to their fourth successive defeat at the last eight.
Nasser Hammami saw his volley tipped out by USMA goalie Mohamed Zemmamouche after three minutes in one of the highlights of the first half of the hotly contested affair.
Four minutes after the break, 30-year old Meftah soared above two defenders of Eulma to head home from a Kaddour Beldjilali corner for the goal that separated the two sides.
The hosts fought back but the equalizer remained elusive, slumping to their fourth defeat.
USMA will next play holders ES Setif in a fortnight before traveling to Omdurman on the weekend of 11-13 September as guests of Merreikh.
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