'Fantastic performance' says Grayson
And not only have Preston won the last five, they have done it without conceding a goal themselves.
Preston put in a ruthless display, opening the scoring on two minutes through Paul Huntington.
Former Oldham player Daniel Johnson doubled the lead after 32 minutes before Joe Garner made it three early in the second half.
Then it was left yo Jermaine Beckford to round the scoring off eight minutes from the end.
Grayson told reporters: 'It was a fantastic performance against a team who are up there in the table.
'That sort of performance has been coming for a while because we've been playing well and making chances. We thought there would be a game when we scored a few.
'The early goal gave us a perfect start and it calmed everyone down against a team with a new manager in charge.
'We built from there, but even in the last five minutes we were still closing down as a team and keeping our shape and discipline.'