Shaun Goater and Andy Hughes scored the goals to send Reading through to the next round with an easy win over local rivals Oxford.
After a slow first half, Reading's class told after the break, with goals in the 62nd and 77th minutes giving them a deserved victory.
A sloppy pass from Danny Brown allowed the away team break quickly to score the opener just after the hour mark.
Hughes headed the ball down for Lloyd Owusu, making his first appearance of the season, and he drove in a shot that was saved by U's keeper Chris Tardif, only for the ball to rebound to Goater who made no mistake from eight yards out.
Hughes made the game safe when Reading again caught Oxford on the break, coolly slotting home first time after Paul Brooker's inch-perfect cross.
The game could of been so different however had Brown not missed a glorious chance for Oxford, cutting inside Graeme Murty only to shoot wide from eight yards out when it looked easier to score.
But the superior ability of Championship Reading was always going to show through. The Royals started the match like an express train, Goater firing inches over the bar after just 47 seconds, before Oxford had even touched the ball.
It looked like it was going to be one-way traffic when Oxford defender Jon Ashton was forced to clear off his line after a goalmouth scramble, but the U's got into the game following a shaky opening half hour.
But Lee Bradbury and Tommy Mooney both headed over crosses and Rob Wolleaston shot wide when he should have done better and they were to pay for their mistakes.
Yet Reading's make-shift forward line of Goater and Owusu continued to misfire dangerously. Owusu miskicked when presented with an open goal and Goater shot wide as they once again tore through the home defence.
Finally Goater made the breakthrough just after the hour and from then on in there was only going to be one winner.
Although Bradbury thought he had scored an equaliser, the linesman ruled his effort out for offside and soon after Hughes made the game safe.
With Oxford 2-0 down and dejected, the game died a death in the closing minutes. Substitute Nicky Forster thought he should have had a penalty late on, but was booked for diving.