The Reds were beaten 2-0 by the top flight outfit at The City Ground and boss O’Driscoll admitted: “It wasn’t pleasant at times.
“I think they found it difficult – we’ve played two Premier League sides and it’s difficult when we haven’t got the ball.
“We passed the ball better against Aston Villa, which gave us a toe-hold in the game.
“Tonight we worked as hard but didn’t pass the ball very well and once they got on top it was very difficult to break the cycle.
“We were going to bring everyone off at half-time and change things around but we decided to keep everyone on.
“We were 2-0 and hadn’t really started and we wanted to see whether we could the way the way was playing.
“Sometimes when you are flying half-time can be a hindrance but it helped us this time.
“Little tweaks and putting the emphasis on different things can make a difference and I thought we started the second half well.
“We wanted to get something out of the game and we’ll take a clean sheet in the second half as a positive.”
Forest are now focussing on Monday’s Capital One Cup first round clash with Fleetwood Town at The Highbury Stadium (kick-off 7.45pm).