Chris Wilder felt his players got caught up in the occasion following the dismissal of Wednesday skipper Glenn Loovens on Friday evening.
Loovens saw red in the 64th minute, following two cynical lunges on Clayton Donaldson, but the Owls held firm to take a share of the spoils from the Lane.
And speaking afterwards, Wilder praised the opposition and was left frustrated at United's inability to capitalise on a numerical advantage.
The manager said: "They sat deep all game, I'm not going to complain about that, it was down to us to break them down, we second guessed it and I'd have done exactly the same.
"They had Joao with pace to get in behind and a target, they flooded the midfield and they hoped to get something on the counter attack.
"They were a dangerous side and one who worked extremely hard, full credit to them.
"We didn't need to get caught up in the atmosphere after the sending off, we needed to step back from the excitement and emotion."
Wilder concluded: "We needed our cool and calculated players to step up, we ended up shooting off balance, putting cross high over the bar, we just couldn't produce that bit of quality.
"We didn't deserve to win the game really and in the end we could have easily lost it, had not been for Simon.
"It was a save he had to get up and make, if he hadn't it was a goal. Fair play to him, their goalkeeper makes a fantastic save from Clayton too.
"But we had 25 minutes to win the game against some tired bodies and we should have kept moving the ball until an overload or opportunity arose, instead of trying to score each time we went forward."