The Posh looked to be heading for defeat losing 3-2 with 21 minutes to go, but the sending off of the Owls` Darren Potter prompted a turnaround with Craig Mackail-Smith and George Boyd netting their second goals of the game and Nathaniel Mendez-Laing also getting on the scoresheet to secure the win.
Ferguson said: "It is a big result on a night when the other teams towards the top all won. I don't think we have done well enough against the so-called big teams this season and that's why it was imperative we got a win here.
"Sheffield Wednesday might be in a poor run at the moment but they are a massive club and will be there or thereabouts come the end of the season."
On conceding three goals, Ferguson added: "I take responsibility for some of the poor defending. We left our right-back Chris Whelpdale far too exposed at times, but we changed things at half-time and were a lot more solid after that.
"It is no secret we have to be more composed defensively and we have to cut out the stupid decisions. You cannot concede three goals on a regular basis and expect to win games."
Source: PA
Source: PA