Matheus Cunha struck twice as Wolves hammered the Cottagers on Saturday.
O'Neil later said, “It’s one of favourite performances probably in my time as a coach. It took a lot of courage and character. When you asked me about the team before the game, I gave a lot of positive messages, but we knew that this was going to be a real tough test because of the players that we were missing, and every single one of the players managed to stand up and do an incredible job.
“It wasn't as if we nicked a win today, I thought we were good value. There were some fantastic goals, some real gritty, hard-working defending, and something that the players deserve because they've worked hard and they've not had too many things going their way so far.
“Since we lost at Brentford, we pushed Man City close, and then we go four unbeaten, so a real good response to a tough afternoon at Brentford.”
On Cunha, he also stated: “His is our talisman. He knows what I think of him – I love him. I love working with him, I love trying to help him get better and the improvements he's made are just incredible. When I came, there was an undeniable, incredible talent, but somebody that didn't fully understand how to make it the most effective and we get him in some great spots now.
“The team know how to utilise him, and he's a great guy. That was probably his best out of possession performance as well. I know I probably drive some people mad talking about out of possession, but it is important to us.
“I know what he’s going to bring with the ball, but today, he fitted very well into our possession structure and led from the front, and brought some unbelievable qualities to the game, and you need it. You can be as well coached and as well organised as you like, but at this level, you do need quality and Matheus brings us that in abundance.”