Goals from Youcef Bellaili, Kaddour Beldjilali and substitute Mohamed Amine Aoudia condemned Setif to their third defeat at the group phase and effectively killing their hopes of reaching the last four as a well as a successful defence of their crown.
With seven points, Merreik are certain to finish above Setif in the event of losses in the next two games, due to head-to-head advantage. The holders are third with four points and Eulma at the depth of the standings pointless. With a record of five win from five matches, USMA will finish as the top placed side in the group and will face the runner-up in Group A for a place at the final.
Needing nothing short of victory to keep their hopes alive, Setif were outplayed by their local rivals in the keenly contested clash, despite the latter already through to the next stage of the premier continental club championship.
The impressive start of the visitors saw USMA goalie saw Mohamed Zemmamouche deny Mohamed Benyettou twice in the opening minutes before the tide tilted the direction of the hosts.
Three minutes past the half-hour mark, Bellaili broke the deadlock, beating an offside trap to profit from a through pass from the middle before shooting past onrushing Sofiane Khedairia.
Four minutes later, the host went up for the second time with Bellaili setting up Beldjilali who struck a low shot that squirmed under Khedairia into net.
USMA continued to dictate the pace of the game and Zineddine Ferhat was guilty of missing a sitter five minutes before the break, shooting wide from a Beldjilali assist with only the Setif goalie to beat.
The visitors struggled in search of their feet after recess, and were unlucky on 69 minutes as Zemmamouche pulled a superb save off Abdelmalik Ziaya’s goal bound volley.
On 74 minutes, new recruit Aoudia who replaced Mohamed Seguer just after the interval took the game beyond his former club with the third goal. The 28-year old, who had a successful two-year stint with Setif between 2011 and 2013, winning two league titles before leaving for Germany returned to haunt his former employers.
From a Belaili cross, his header was saved by Khedairia before slamming home the rebound to seal victory.
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*All times are in local time