Fulham midfielder Ryan Tunnicliffe went down in the Wednesday box before poking the ball to goalscorer Matt Smith in the 75th minute.
Manager Kit Symons was unsure about Tunnicliffe's tumble but was pleased with the impact of his substitutions.
"I was appealing for it (a penalty) as you would imagine but, listen, either way I was just pleased to have got the goal in the end," he said.
"I thought it was a good break from us actually, good build-up play. They were appealing for offside against Matt but I spoke to some of their guys afterwards and they were quite happy that he was onside in the end.
"We were a goal down away from home and we needed to get something out of it so I had to make positive substitutions and act quite early and that's what we did and it paid off on the day. It doesn't always work like that, trust me.
"We knew about the state of the pitch coming into it. I spoke to Stuart about it before the game and I said to our players it's not an excuse. It's a factor and it needs to be played accordingly but it's the same for both sides. It is what it is and you get on with it."