Lewis McGugan opened the scoring for Forest before Barry Bannan pegged them back with a magnificent free-kick. Marcus Tudgay restored the hosts' lead before McGugan scored a free-kick of his own to put the game beyond the Premier League side.
O'Driscoll told the club's official website: "I didn't enjoy the first half, I got a bit frustrated because I'm a big believer in what you do in training should be replicated in a game. I thought they lacked a little bit of conviction to do the things I've seen them do day in, day out.
"I think we've got to look beyond the result. I've said before we've got to look at the performance first and I'd have done that if we'd have lost 3-1. There are aspects of the performance we can improve on, there's an understanding we can improve on.
"It was difficult because it's the first time we've played in front of a home crowd so everyone was a bit tentative but we flipped the structure after 20 minutes because it wasn't working for us and we ended up playing some really good stuff.
"As we got on, we got better and better and we had the luxury of bringing nine or 10 players on. (Villa boss) Paul [Lambert] decided to keep most of his on so tiredness made a difference and we exploited the space really well towards the end of the game - credit to the players."
