Grayson made one change to the side that beat Notts County with Humphrey returning to the side in place of Robinson. North End took control of the game early on and never looked like spoiling their home record of only one league defeat at Deepdale this season.
Swindon made several changes to their side in a bid to rest key personnel ahead of a play off campaign as the visitors will now finish the season in fourth spot.
Preston started the game int he best possible fashion with Gallagher crossing for Garner to head hom with around a minute on the clock. It set Preston up nicely for the rest of the game.
The visitors tried to play theball out from the back but high pressing from Preston eventually made Swindon take a more direct route at times but it all made for a great game.
Garner netted his second just before the break which settled all nerves in front of the biggest leeague crowd of the season. Again Gallagher was the provider from a set pieve.
The game was then over shortly after the break. Beckford smashed a shot against the bar and the rebound fell to Garner who hit home to complete his hat trick.
The MK Dons defeated Rochdale knocking them out of the play-off race. Preston now travel to Colchester on Sunday who will still be fighting for survival but a victory will secure second place and automatic promotion for Preston.