Manning was berated by large parts of the angry support after presiding over a seventh straight Carrow Road defeat, six of those in the league for the relegation-threatened Canaries.
The City chief was also quick to apologise to furious home supporters after he headed down the tunnel at the final whistle, rather than join his players and staff on a lap of appreciation.
Fans also protested outside the stadium both before and after the game, with more calls for sporting director Ben Knapper to follow Manning out of the exit.
The under-fire head coach spoke to the media at Carrow Road on Saturday afternoon.