Defeat saw Preston slip out of the Championship play-off places after a run of three matches without a win.
The Lilywhites had lost their last four games against the Berkshire side and, with the Royals coming off back-to-back victories, the stage was set for a testing afternoon for the hosts.
Reading took the lead with their first attack, with what proved a real cracker.
They soon doubled their lead. Blackett was again the provider, this time he slid a ball to Joao and the Portuguese forward fired left-footed across the sprawling Rudd, who got a hand to it but couldn't prevent it nestling in the far corner.
It seemed that the Royals had made it three when Ovie Ejaria struck the upright with a long-range piledriver, Joao put the rebound in the back of the net, but the assistant referee flagged for offside.
Roared on by an expectant crowd, Preston improved after the break and created chance after chance.
First Billy Bodin let fly from 20 yards and forced Cabral into a stunning finger-tip save.
A weak back header by Ben Davies saw Joao sneak in but his prod was well saved by the on-rushing Rudd.
It was wing-back Hughes' left foot that was relied upon to swing the crosses into the Reading box but even substitute Jayden Stockley, renowned for his heading ability, could not convert.
The Royals played Joao as a lone striker in the second half and he struggled to feed off scraps in a complete contrast to the first half.
But ultimately it was a disappointing afternoon at Deepdale for the team in white who will rue giving their mid-table opponents a cushion that they defended so well.