Two late penalties from John Carew sealed victory after a spot-kick from Palace's Darren Ambrose had cancelled out a first-half goal from Gabriel Agbonlahor.
But O'Neill was pleased that none of his players appeared to have the weekend meeting with Manchester United on their minds as they gave a typically determined performance.
O'Neill said: "We went strongly with our side in this game and injuries are always a risk but the players were prepared to take that risk.
"All the players were prepared to go for it tonight and I did not see one shirking anything at all ahead of Sunday.
"That speaks volumes for the team and the tremendous commitment they showed in addition to the fantastic ability they have."
O'Neill admitted a couple of his players had picked up knocks but will have a better idea of their fitness tomorrow.
He said: "I stayed a bit longer in the dressing room to find out about one or two of them and we will have a better idea tomorrow morning."
Regarding his team's performance, O'Neill said: "We went very strongly at the game and deserved to win it.
"We spurned a lot of chances and needed a second goal. Palace played some good stuff in the second half but we got through in the end."
Palace manager Neil Warnock again made little comment about his future amid speculation he is bound for QPR.
But Warnock did confirm that he will be in charge of Palace for Saturday's game at Doncaster.
He said: "This could have been my last game - but it won't be and we'll now get ready for Doncaster.
"Can I deny speculation about going to QPR? No."
Warnock was proud of his side's performance but again felt Villa should not have been awarded a corner from which Ashley Young created the opener for Agbonlahor.
He said: "It was a goal kick. You could see that from the halfway line. This sort of thing does my head in at times.
"But Villa deserved to win although I think the scoreline was a bit flattering. They are a top side and we really had to hang in there to give them a good game."