Chris Robertson scored the only goal of the game as Preston beat Huddersfield, who still have to wait to confirm a play-off place.
Defender Robertson, set up by Danny Mayor, netted from eight yards as the Terriers slumped to their third successive defeat.
Chris Holroyd hit the post for the hosts with a volley as they went in seach of a second goal.
At the other end, Jordan Rhodes saw a header fly inches wide.
VIEWS FROM THE DRESSING ROOM
Huddersfield Town manager Simon Grayson told BBC Radio Leeds:
"We played so well in the first half and I thought the system worked - we played three in midfield and passed the ball around well.
"In the second half we switched off, somebody didn't do their job and then suddenly we conceded and looked too open.
"You can't fault the players' endeavour and attitude. In the first half I thought we very good and we kept going until the end, but we huffed and puffed without blowing that spark out."