Wilder later said: "It's the story of our season. There's been times when we've been well and truly put to bed. But there's been nights like tonight.
"Add it all up. We went toe-to-toe for 80 minutes, we got ourselves in front a couple of times. But it was the same old things that have come back to haunt us, poor defending.
"I've got to say, I'm really disappointed with a couple of the decisions as well. I think the free-kick, I don't know what my centre-half is supposed to do, just walk out the way? He's nutmegged him, but he can't disappear. That said, we've not really defended that situation as well as we should have done.
"I think he's blown early on the penalty. I think it's a really soft penalty if I'm honest about it. There is always contact in the box. It's a really soft one. Now, you might say they scored. But that's got nothing to do with us. He gave a penalty straight away.
"Yet again, it's a mixed bag. A lot of things are pretty good. A lot of times we get pretty close. But we are here, it's another one we've lost.
"The inevitable will happen, we understand that and accept that. We're in a position where we just have pride to play for. We did that and the supporters recognise that.
"There's bodies in there we can build and rebuild around. Going into next season there's a big rebuild on. We, I, have to make sure we get the culture right.
"We've scored two at Old Trafford and we've come away with nothing. That's something that shouldn't be happening. You should be getting something out of the game."
On Brereton Diaz being a star for the Blades, he added: "Absolutely spot on, I did my homework on him and knew what he was like as a lad and as a player. He's been outstanding."