At a very wet Sixfields Scott McGleish put the home side in front but two minutes later Leroy Lita levelled.
Reading then went on to wrap up a comfortable victory with goals from Kevin Doyle, Brynjar Gunnarsson and Simon Cox.
The start was delayed for 10 mins becuase of the stormy conditions. A steward was reportedly struck by lightning before kick off.
Reading: Stack, Murty (C) (Osano 65), Shorey (Makin 60), Sonko (Halls 60), Ingimarsson, Sidwell, Gunnarsson (Pearce 72), Little (Oster (60), Ki-Hyeon (Golbourne 66), Lita (Cox 65), Doyle (Long 65).
Sub not used: Federici.