Substitute Eoin Doyle helped to ensure Preston avoided an upset at home to Sky Bet League One Oldham as they secured a 2-0 victory to reach round three of the EFL Cup.
Striker Doyle scored just seven minutes after his introduction before teeing-up Jordan Hugill for the second in the first League Cup meeting between the two north west sides since 1968.
After a slow start to the match, it was Oldham who fashioned the first half-chance in the 18th minute as Josh Law slid in Marc Klok inside the area but the midfielder scuffed his effort from 15 yards and Paul Huntington cleared.
That appeared to spark Preston into life as three minutes later Ben Pringle's free-kick found Hugill at the far post and his header from four yards was saved low to his right by goalkeeper Connor Ripley.
Simon Grayson's side, who picked up their first win of the season at the weekend, threatened again after half an hour as Ben Pearson teed-up substitute Alan Browne but his strike was well over the crossbar from 15 yards.
Oldham, who knocked out Championship side Wigan in round one, were not being overawed by their higher-ranked opposition and came close after 51 minutes when Lee Erwin unleashed a fierce left-footed drive from 20 yards which was held by Preston keeper Chris Maxwell on his competitive debut for the club.
From the resulting clearance, Maxwell picked out Simon Makienok - making his first start for North End - and the striker flicked on for Hugill who drifted a header wide of the far post.
Makienok was making a handful of himself again five minutes later, knocking down for Browne to strike wide from 20 yards.
The game had come to life since the break and Erwin came close again for Oldham after 58 minutes, firing a powerful drive straight at Maxwell from 20 yards before Law shot wide of the far post from the rebound.
Oldham had kept three consecutive clean sheets but their defence was finally breached after 66 minutes. Substitute Doyle collected Greg Cunningham's cross on the penalty spot and scuffed a left-footed shot past Ripley and into the bottom corner.
Steve Robinson's side, who have not reached round three since 2002, looked to bounce straight back as substitute Darius Osei skipped through the Preston defence five minutes later but fired his effort comfortably wide of the far post from 12 yards.
But Preston secured their progression to round three 10 minutes from time thanks to an error from Oldham keeper Ripley.
He came out to the left wing to clear the ball but was caught in possession by Doyle, who crossed to the far post for Hugill to nod into the unguarded net.