Now he has ended that drought, O'Neill hopes he can finish the season with a flourish - starting against Palace.
O'Neill said: "His confidence has been boosted with his two goals against Burnley.
"I think he has been doing very well for us without getting the occasional goal.
"That is the part of his game which he feels he can improve upon as he has a really good shot and I think his two goals against Burnley will have lifted him enormously.
"He is a confidence player and you can see the ability he has.
"I think he is able to contribute more in future in the way of goals after scoring against Burnley. He has a strong shot and we often see it in training.
"Overall I am very pleased for him because I think some of his performances over the last couple of months have merited bigger notices than he was getting.
"His goalscoring form has come at a good time and I know the England manager has certainly said in the past how much he thinks of Stewart Downing. That will be very positive for him."
While Villa seem to have rediscovered their eye for goal after scoring 10 in their last five games, O'Neill is confident his defence can keep Palace quiet at the opposite end of the pitch.
Villa were undone by two set piece goals when their first meeting ended in a 2-2 draw at Selhurst Park.
But they have the meanest defence in the Premier League - conceding just 21 goals in the top flight so far - and O'Neill added: "A very big plus for us this season has been the inclusion of such players as Stephen Warnock, James Collins and Richard Dunne.
"Dunne is kind of quiet but he is natural leader as he leads by example. For anyone who comes into the side I would think that the confidence the other players are exuding should rub off on them."
Victory for Villa against Palace would take O'Neill closer to unchartered territory in the FA Cup.
The furthest he has ever gone is the quarter-finals and victory against Palace would set-up a place in the last eight against either local rivals West Brom or Reading.
He said: "The quarter-final is the furthest I've been in the FA Cup. I've done it three times as a player at Nottingham Forest, Norwich and at Notts County.
"At County we were beaten by Everton in front of a big, big crowd of about 230! That was 1984 and Everton went on to beat Watford in the final.
"So it would be great to get into the quarter-final this season."
Villa skipper Stiliyan Petrov, whose late goal at Selhurst Park earned O'Neill's side their replay, is battling to shake off a virus in time to figure.
If he is ruled out, it will heap more responsibility on 18-year-old midfielder Fabian Delph.
O'Neill has no doubt that the talented teenager can cope and he added: "I have been very pleased with Fabian Delph. I know he is exceptionally hard on himself. Sometimes that is not a bad thing.
"I am expecting really big things from him in the not too distant future. He has real talent and a real chance to make an impact."
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