An encouraging first half hour was stopped in an instant as Pol Valentin was adjudged to have fouled his tormentor Josh Ginnelly in the box. From there things spiralled.
Wednesday were passive and unable to muster anything in the way of attacking promise - their defensive efforts scrappy and well punished.
It leaves the Owls still without a win this campaign having playes eight league matches - and two in the cup.
They are the only team yet to win a game after round eight of the Championship season.
Here are our player ratings from a horror trip to South Wales.
5. Pol Valentin - 2
He’s had horrors and he’s had brighter games. It was the former in South Wales. Ginnelly made the most of his penalty claim but he tugged him back. Looked completely unable to cope with the wide man until he came off injured. Pass completion at one stage was as low at 52%. | Ellis / UGC
6. Jeff Hendrick - 3
Carded having got the wrong side of things late on in the first half. Passive and unable to muster much. | Steve Ellis / UGC
7. Barry Bannan - 4
Jumped into life to firefight a Swansea attack on 10 minutes after a mis-step from Vasquez. Put in a couple of good crosses on an afternoon devoid of any spark. Looked dejected and was unable to raise anything from those around him. | UGC / Steve Ellis
8. Juan Delgado - 2
Twice caught offside looking down the line in promising attacks. Offered very little. Hooked with over half an hour to run. | UGC / Steve Ellis