The Sun is reporting that Jose Mourinho's Red Devils stars vented their frustrations at being 2-1 down to their neighbours at the break by having it out with each other in a serious manner.
It is understood that Mourinho did not deliver the Sir Alex Ferguson-style 'hairdryer', rather the playing group themselves who were behind the clear-the-air discussions.
A source told The Sun: "The hairdryer came out for the first time this season, but it had nothing to do with Jose.
"The players could be heard shouting and arguing amongst themselves during the interval. Jose decided to let them blow off steam for a couple of minutes.
"He then quietened the whole situation down and told them they also needed to calm down or the second half could be much worse.
"Goodness knows what it would have been like if Zlatan (Ibrahimovic) wasn't handed that gift."
However, the talks obviously did not work as United would have liked as they were unable to make headway into the one-goal deficit during the second half and eventually lost their first match of the season to Pep Guardiola's impressive City.