Lee Hughes made his long-awaited Oldham debut, but his new team crashed to a heavy defeat away against Hartlepool.
Oldham did take the lead when Craig Davies rifled home, but the hosts levelled shortly after when Ian Moore converted Andy Monkhouse's centre.
James Brown finished from a tight angle to put Hartlepool ahead and Richard Barker extended the lead from the spot after he was fouled by Sean Gregan.
Substitute Joel Porter wrapped things up with a well-taken late fourth.
Hartlepool: Budtz, McCunnie, Nelson, Antwi , Elliott, Brown (Porter 64), Liddle, Sweeney (Humphreys 37), Monkhouse (Foley 76), Moore, Barker.
Subs Not Used: Lee-Barrett, Clark.
Goals: Moore 15, Brown 26, Barker 44 pen, Porter 83.
Oldham: Crossley, Eardley, Thompson (Trotman 52), Gregan, Bertrand, Liddell (Pearson 52), Kalala (Allott 54), McDonald, Taylor, Davies, Hughes.
Subs Not Used: Pogliacomi, Lomax.
Booked: Kalala, McDonald.
Goals: Davies 14.
Ref: Rob Shoebridge (Derbyshire).