John Stones produced a 95th minute winner for City after teammate Josko Gvardiol had canceled out Jorge Larsen's opener for Wolves. Stones' winner was ruled legit after initially be denied for offside.
O'Neil later said: "Performance was excellent, I thought the lads gave absolutely everything. We kept finding the answers and we concede a controversial goal late on. The things that could go against us today definitely did but we have to take positives and we have to get ready for next weekend against Brighton.
"It's tough defending for so long, it is so hard to get out. They were working their socks off, they gave everything, they showed what they are which is all I asked. We need to make sure it looks like that more often.
"The players are down as you would expect. For all the hard work that has gone into that, to then leave with hard luck stories feels like a big blow of course. I was very critical of them at Brentford. Today was a return to more like what we need to be.
"It has been such a cruel run of fixtures. We need to keep standing up. We are where we are and we need to make sure we keep producing the best of ourselves.
"I knew Bernardo Silva was close to the goalkeeper. Against West Ham we were given the reason of close proximity. Silva is less than a yard away and I think that same reasoning should be applied to this one, but it wasn't. I was calm about it, unfortunately there is nothing we can do."