They won 2-1 with goals from Jon Parkin and Sean St Ledger but that was only the story.
For them to gatecrash the top six, they also needed Cardiff City to slip-up in their visit to Sheffield Wednesday.
Cardiff obliged and PNE pipped them to sixth place by just one goal having finished on the same points. How important their 6-0 win over the Welsh side a fortnight earlier was to prove.
It sparked joyous scenes at Deepdale, North End supporters swarming on to the pitch at full-time to celebrate reaching the play-offs, something which had looked beyond them a few weeks earlier.
Four wins on the bounce, including that huge swing result against Cardiff, changed the dynamic.
Beating QPR was no straight-forward assignment.
The Londoners, managed in a caretaker capacity by former Preston favourite Gareth Ainsworth, pegged PNE back at one stage in the second half.
Ex-North End striker Patrick Agyemang was the man with the visitors’ equaliers but thankfully the Lilywhites found a winner.
Mikele Leigertwood and Rowan Vine had chances for QPR as play went from end to end in the first half.
Neil Mellor, Sean St Ledger and Simon Whaley all got in good positions as North End built up some momentum.
That pressure paid off seven minutes before the interval when Alan Irvine’s men took the lead.
QPR centre-half Kaspars Gorkss messed up an attempted back pass, allowing Parkin to steal in and home in on goal.
The ‘Beast’ took the ball past keeper Radek Cerny to the right of goal and then finished with a low shot from the narrowest of angles.
Early in the second half, St Ledger nodded the ball back across goal but Billy Jones was unable to get much power on his header
QPR equalised in the 57th minute, Agyemang turning smartly in the box and rolling a shot across Andrew Lonergan.
That briefly dampened the atmosphere but the volume was soon turned up when news filtered through that Cardiff were losing.
North End went on the attack, Mellor putting two good chances over the bar.
Left-back Eddie Nolan tested Cerny with a free-kick, one which the keeper got his fingertips to. They regained the lead with 15 minutes left.
Parkin launched a long throw into the box, substitute Chris Brown flicked it on and there was St Ledger to send a header into the roof of the net.
North End were not prepared to rest on their laurels, continuing to pile on the pressure.
Parkin put a shot too close to Cerny, after Brown had played him in.
As the clock ticked on, QPR applied some pressure of their own, causing a few anxious moments in the PNE defence and among the crowd.
The blast of the final whistle from referee Michael Oliver brought a mixture of joy and relief.
With it confirmed that Cardiff has lost, North End had sneaked into the top six and set up a two-legged semi final with Sheffield United.