David McGoldrick picked the ball up in space and hit a tame daisy-cutter from 25-yards for the first shot of the game for Forest which was saved by Preston goalkeeper Andrew Lonergan in the 18th minute.
Preston striker Neil Mellor had a surging run from his own half down the inside right channel with no Forest players near him and Ross Wallace was to his left begging for the pass which was delivered to perfection.
Forest goalkeeper Lee Camp closed him down but Wallace scored in the 20th minute with a goal from the edge of the penalty box into the bottom right corner of the goal.
Wallace's left-foot left-wing out-swinging corner led to Chris Gunter manhandling Billy Jones to the ground and referee Mark Haywood gave a penalty.
Preston left-back and captain Callum Davidson's left-foot penalty was hard and low, straight down the middle in the 29th minute.
Matthew James picked the ball up after a well-worked move from Chris Brown and Wallace's assist and hit the ball with all his might into the far top right corner from 20-yards out in the 32nd minute.
Liam Chilvers replaced Youl Mawene who limped off with a strain in the 41st minute.
Luke Chambers replaced Lewis McGugan at half-time.
Sean St. Ledger was shown a yellow card in the 52nd minute for a clumsy challenge on McGoldrick.
Mellor had a shot saved in the 55th minute.
Jones fouled Chris Cohen just inside the box and Dexter Blackstock slammed the penalty low and hard into the bottom corner to make it 3-1 in the 57th minute.
A minute later Chambers crossed and Blackstock's shot was saved.
Wallace was booked in the 61st minute and Davidson in the 67th minute for a foul on Gunter.
Robert Earnshaw replaced George Boyd in the 69th minute.
Earnshaw made it 3-2 when he was played clean through the middle by Blackstock and calmly slotted the ball over Lonergan in the 76th minute from inside the area into the bottom right corner.
Richard Chaplow replaced Mellor and Dele Adebola replaced Paul Anderson in the 80th minute.
Keith Treacy replaced Chris Sedgwick in the 82nd minute.
Blackstock was booked for a blatant dive in the Preston box in the 85th minute.
Wes Morgan was booked for a foul on Davidson in the 89th minute.
Chaplow fouled Kelvin Wilson and both were booked in the 90th minute.