Before Bernardo Silva set Manchester City on their way to a derby schooling at Old Trafford, the team analysts were fuming with Benjamin Mendy.
Every time they wanted him to turn to his left and up the field in the opening minutes of the game, he kept his body position as it was and passed back into the middle - where the trouble lay. Desks were banged and actions gesticulated and while the opening may not have been the prevailing narrative on the night, it will not have been forgotten.
Nearly three years after signing, Benjamin Mendy - largely due to injury - has still not nailed down the first-choice spot at left-back and there are again talks of the club being interested in Leicester City's Ben Chilwell. The England international was looked at a year ago when the Blues first considered strengthening in that position and has only enhanced his reputation in the months that have followed.
Being pushed aside at Wolves blotted his copybook over Christmas but it is hard to think of a spell where Mendy has looked better for the Blues. This was his eighth start in the last 11 games and arguably his strongest performance yet.
From the off, he was utilised as a threat on the left wing with teammates falling over themselves to set him up to whip a delivery into the box. In a performance where City were not quick or direct enough, he looked the most likely after Kevin De Bruyne to create a goal - which is to say the best human effort on the pitch.
Where there have been three left-backs in some matchday squads this season, Pep Guardiola named just one against Crystal Palace and whatever other struggles there were in the performance the left-back position was an unexpected strength.
That isn't to say that it was perfect - he got a telling off from his manager after picking up a needless booking in the second half - and there is a long way to go with his form and his fitness before he can be considered a reliable option for the long-term.
But he is learning and improving, even from the game a few weeks ago with United. If the manager is looking for improvement for next season, a player that has shown the right reaction to criticism is in a good position.
Producing the assist that should have completed the turnaround against Palace, a delicious cross onto Sergio Aguero's head, can't hurt either when his pros and cons are weighed up.
City may be looking ahead, but Mendy is facing forward now too.
