Young set up the opening goal for defender Martin Laursen and scored the second himself before limping out of the action with a groin injury.
Young has already forced his way into the England squad and O'Neill is optimistic the former Watford player can climb to the top of the footballing ladder.
O'Neill said: "Without doubt, Ashley is fulfilling the potential he had during his time at Watford and he has turned in a string of excellent performances.
"When he came here, he took a while to find his feet after scoring on his debut but you can see now his confidence is sky high and he has that ability to go past players.
"I believe he can become a really great player. He came in for a bit of harsh treatment today but he is expecting that and Derby were going to play hard.
"But at the moment his confidence is so high he feels something is going to happen every time he gets the ball.
"In the first half he was starved for a bit of the ball and I don't think he touched it for about 10 minutes but once he started to get hold of it he was a real handful."
O'Neill remains optimistic Young will have recovered from his injury in time for the derby with Birmingham City at St Andrews next weekend.
Villa, who have now won five of their seven home games this season laboured in the opening 45 minutes before Laursen and Young struck in the space of four minutes early in the second period.
O'Neill said: " In the first half we were on the back foot and couldn't keep the momentum going. At home we should be more forceful and in the 10 minutes before half-time things were very flat.
"I said at half-time we had to make things happen, not just sit there and wait for them to happen, credit to the players, we turned it around.
"There was more purpose about our game in the second half when Nigel Reo-Coker produced the sort of performance he's capable off."