Ophir blazed to a 25-0 Qualifying 3 success over Letterkenny at Magowan Park.
The Mallusk men were reduced to 14 when number eight Conor Bond sustained an elbow injury but they battled on to a big win.
Second row Phil Adgey crossed for the first of his two tries after some neat play from a line-out, before James Milligan struck a penalty to put the hosts 8-0 in front.
In the second half a clinical maul and drive led to a try for Patrick McCabe which was converted.
Milligan then dispatched his second penalty to make it 18-0. The visitors lost their scrum-half to injury before Adgey landed his second of the day to wrap things up.
Ophir are up to fourth in the table ahead of Saturday’s trip to Civil Service.