After their first clash ended in a 1-1 draw, it was a totally different affair on Tuesday night.
Chelsea loanee Tammy Abraham scored his first goal since October to kick off the rout.
He then set up Nathan Dyer for the Swans second, before the winger doubled his account ten minutes later.
Noor Husin pulled one back for the visitors but it was only a temporary reprieve.
Abraham then had a brace when he completed a beautiful team move on the stroke of half-time.
Defender Kyle Naughton made it five eight minutes after the restart.
The Swans will now take on Sheffield Wednesday in the fifth round.