Goals from David Nugent and Richard Creswell put Preston in pole position for the play-off semi-final second leg at Derby after a 2-0 win at Deepdale.
Billy Davies' North End totally dominated the opening period and, after Cresswell had missed a couple of chances, Nugent put the hosts ahead in the closing stages of the first half.
Following an abject performance in the opening period, the Rams were much better after the break.
But the better chances still fell to North End and they came up with a fortunate second goal in the final minute.
Mo Konjic, attempting to head clear a cross, instead headed the ball down into the turf and it bounced off Creswell's boot and past Derby keeper Lee Camp.
