The Royals breezed through by overcoming League 1 opposition for the second consecutive round thanks to a wonder showing from Gareth McCleary
Reading started like a team that had taken four wins from its last five games and within six minutes, it was ahead when a floating Hal Robson-Kanu cross met the head of Noel Hunt, who rose well and steered it into the far corner.
That early shock seemed to compose the visitors however, and mid-way through the first half, Nick Blackman comfortably eased past Nicky Shorey before producing a drilled cross that left Chris Porter with the goal gaping. However, the Blades' number nine somehow failed to make any contact from all but two yards out.
Buoyed, Danny Wilson's men went close to levelling through Porter again but his flicked header could only drift just wide before Jamie Murphy latched on to some good link-up play from Kitson to fire in a shot that was straight down the throat of the Reading goalkeeper.
However, the League 1 outfit was left to pay for its profilgacy when with halftime closing in, Mikele Leigertwood reacted quickly to a blocked Le Fondre shot, exchanged passes with wideman Gareth McCleary and produced a rasping drive that nestled in.
That second goal seemed to knock the stuffing out of the visitors and within 10 minutes of the start of the second half, the Premier League side found itself four goals to the good. First, Hunt claimed his second of the afternoon when he expertly swivelled and finished after fine wing play from McCleary, before the former Nottingham Forest speed merchant burst into the box, and eased inside a Blades defender before slotting it past the hapless goalkeeper.
From there, the tie was played at a pedestrian pace but Stephen Kelly still needed to be on his toes on the Reading goal-line to clear what would have been a consolation strike from Danny Higginbotham.
However, that proved to be the last real chance of note for either side as Brian McDermott's men continued their recent fine form.