Defensive errors helped give Preston a 2-0 half-time lead before the Latics pulled one back in the second half from 25 yards.
Oldham were reduced to 10 men near the end when Matty Carr received the red card. Preston restored a two goal lead on the stroke of full time.
The next match is on Monday 6th December at 7pm in the Third Round of the FA Youth Cup with a home tie against Swansea.
Swansea are currently second in the South West Conference with 14 points from 7 games, one point behind leaders Swindon. The Swans missed the chance to lead the table at the weekend as they could only draw 1-1 at home to Yeovil whilst Swindon's match at Bristol Rovers was postponed.
Due to the FA Youth Cup, the league match against Burnley due two days earlier has been postponed and a new datewill have to be arranged.