Andy Morrell's two goals in the first twelve minutes effectively ended this Welsh derby as a contest.
Morrell opened the scoring after 10 minutes, heading home a Darren Ferguson free-kick. Then two minutes later the striker claimed a sixth of the season, sliding home after being set up by Hector Sam.
Trinidadian Sam made it three on the half-hour when he powerfully shot home, before Carlos Edwards beat two defenders and fired home a fourth after 56 minutes.
Morrell also had a penalty claim turned down in the second-half, but it had little effect on the game as Swansea struggled to feature at all as an attacking force.
Swansea boss Nick Cusack said: "In a Derby game like this I want players to show some pride but we laid down and took what they gave us. I can't accept that".
He added: "Our defending was chronic again and the score speaks for itself. It didn't help when we conceded another goal when the keeper called for the ball but did not have a chance to get it."
From the home camp manager Denis Smith said: "I can't complain because if you win 4-0 you have to be happy. But we were better in other games.
"The home draw against Everton in the Worthington Cup, made just before the kick-off, had made no difference to the players performance. It was just a question of getting three points and concentrating on the league for the day