The game turned in the 17th minute when Huddersfield were reduced to 10 men following the dismissal of defender Murray Wallace.
He was shown a red card for hauling down Huddersfield-born Cameron Jerome when he had a clear run on goal and although the Terriers held out until half-time the floodgates opened upon the resumption.
Norwich were ahead within 46 seconds when Gary Hooper set up Bradley Johnson and quickly made it two, with half-time substitute Nathan Redmond heading home Martin Olsson’s cross.
By the 50th minute it was 3-0, with Johnson pouncing on a blocked shot from Jonny Howson to fire home and it was then merely a question of how many the hosts would score, with Cameron Jerome (67) and substitute Lewis Grabban (77) making it five.
“You can’t start that way in any game of football and expect to get anything from it,” said Powell. “It was so unlike us. In the first half I thought we coped okay with going a man down but after the break we weren’t at it and we got punished. Now I have got to pick them up and then we’ll go again. I have certainly got some decisions to make about my next team.”
Powell accepted Wallace had to go. “We didn’t deal with the first ball and we certainly didn’t deal with the second. The referee had a decision to make, and it was the correct one.”
Norwich: Ruddy, Whittaker, Martin, Cuellar, Olsson, Tettey, O’Neil (Redmond 46), Johnson, Howson, Jerome (Hoolahan 72), Hooper (Grabban 76). Unused substitutes: Turner, Lafferty, Hooiveld, Rudd.
Huddersfield: Smithies, Smith, Hudson, Wallace, Robinson, Hogg, Coady, Butterfield, Scannell, Holt, Wells (Dixon 46). Unused substitutes: Gerrard, Vaughan, Ward, Hammill, Allinson, Peltier.
Referee: M Brown (East Yorkshire).
Man of the match: Bradley Johnson.