But Young grabbed the equaliser and his display from the flank inspired Villa to a second-half revival which culminated in four goals in 13 minutes from Stewart Downing (2), Emile Heskey and Gabriel Agbonlahor, before Martin Paterson pulled one back at the end for the visitors.
O'Neill said: "Ashley was terrific for us today. He wanted to make things happen. I was delighted with his performance.
"I have this argument every week with people who say that his form has dipped this season but I think he has done brilliantly.
"It's just been the case that other players have sometimes stolen the limelight, like James Milner.
"I've been delighted with both of them - and a few others besides."
O'Neill admitted: "We started slowly. We didn't get into gear in the first half and were sluggish.
"But, in a game where expectations were high for us to win it, to come from behind was very pleasing.
"There was relief with the equaliser when Downing scored a great second goal and then we had a spell where we were electric.
"In that spell, the movement was terrific and we also had the ability to finish moves off - which has not been our strongest point."
O'Neill admitted Agbonlahor had played despite suffering a calf injury in training on Saturday.
He will assess the fitness of the England striker before deciding whether or not to risk him in Wednesday's FA Cup fifth-round replay at home to Crystal Palace.
O'Neill said: "Gabby had recovered from his ankle problem but hurt his calf in training yesterday and was quite sore so I will see how he feels tomorrow."
Burnley manager Brian Laws admitted his side paid the penalty for "a crazy 12 or 13 minutes" when Villa took them apart after the interval.
The Scot said: "In the first half we were excellent and the game plan was spot on. We deserved to go in front and were bright, organised and solid.
"But what we didn't do was regroup well after the equaliser and the second goal was the killer.
"It was very sloppy and led to a crazy 12 or 13 minutes that lost us the game - and you can't rectify anything after that.
"We didn't capitulate - but we were too expansive with our play."
However, Laws is adamant Burnley will end their away hoodoo and a run of only one point this season away from Turf Moor.
He added: "We will get the result away from home. We will break this barrier. I am confident about that."
Aston Villa 4/11, Draw 7/2, Crystal Palace 17/2