Oldham gave League One newcomers Yeovil a harsh welcome to the division as they eased to victory at Boundary Park.
Latics boss Ronnie Moore gave debuts to eight of his 12 summer signings and two goals in as many minutes put paid to the visitors.
Oldham took the lead when a long throw from defender Rob Scott caught out Yeovil's defence and striker Chris Porter stole in to head home.
Paul Warne added a second when he converted Richie Wellens' cut back.
Oldham: Day, Forbes, Branston, Owen, Tierney, Scott, Wellens, Butcher, Liddell, Warne, Porter.
Subs Not Used: Pogliacomi, Stam, Facey, Bonner, Edwards.
Goals: Porter 24, Warne 26.
Yeovil: Collis, Amankwaah, Skiverton, Sodje, Jones, Terry (Miles 84), Way, Johnson, Poole (Gall 65), Davies (Oliver 62), Jevons.
Subs Not Used: Weale, Lindegaard.
Ref: U Rennie (S Yorkshire).