Goals either side of half time from Papiss Cisse and Yoan Gouffran proved enough to see off the Championship outfit and book the Magpies' place in round four.
"It was a super performance. I am still hurting from Saturday, if I am honest because I can see on the training ground that we have got the squad in a good place," Sky Sports News quotes him as saying.
"All the guys who came in tonight have done terrifically and therefore, that compounds the result on Saturday.
"I am not going to get carried away tonight. We are in the last 16, as we should be, but it's a reminder to us that we have got to get consistency at this football club and if we have got the group below as good as that, then that bodes well."
Newcastle will entertain Manchester City at St James' Park in the next round.