"At this stage, just to try and get through was our priority. If we can continue to make progress in the league, obviously we'll have a look at it, but I felt it was the FA Cup third round, a big day in the calendar, also our Uefa Cup matches are not until mid-February so this was big. I'm delighted now that we didn't get beat."
Manchester United have posed major problems for Villa in the FA Cup, with the Midlands outfit having gone out at the hands of United four times in the previous seven seasons, and O'Neill was pleased to avoid them in the fourth round.
Instead his team will face a trip to either League One Cheltenham or Championship side Doncaster, who meet next week after their original tie was called off on Saturday due to a frozen pitch at Whaddon Road.
O'Neill added: "I'd like to have been at home. Obviously I'm delighted we've missed out Manchester United.
"I will get a great opportunity obviously to watch the two teams play because the game has been postponed.
"It'll be another difficult afternoon for us, but if you'd said to me beforehand that we'd be in the hat for the next round, I'd have been delighted to have taken it."
James Milner opened the scoring for the visitors with a well-taken goal, but Simeon Jackson levelled for the home side with a superb finish before Milner won it from the spot after Adam Miller fouled Ashley Young.
Gillingham manager Mark Stimson was delighted with Jackson's goal – his 12th of the season – even though his performance may have attracted more potential suitors for the 21-year-old. With Ipswich reportedly interested, Stimson is hoping to keep hold of one of his star turns this month.
He said: "He will one day play higher than League Two, but hopefully it's not in the next three to six months.
"I'll be doing my utmost best to say no to any bids, but at the end of the day it's down to the chairman. Every player has their price but we hope my phone stays quiet this January."