Manchester commuters were greeted with a traffic sign that said 'Manchester is red' on Wednesday, as Transport for Greater Manchester reminded Blues of Saturday's derby loss.
City went into the game as firm favourites to win but were beaten 2-1, with goals from Marcus Rashford and Anthony Martial sealing all three points for United.
The result moved United up to fifth in the Premier League table, eight points behind the Blues, who ended the weekend in third spot.
A TfGM sign read: "MCR is red! Make traffic green! Use bus/tram for Old Trafford Thurs 8pm."
United are back in action on Thursday as they host AZ Alkmaar in their final Europa League group game, while City face Dinamo Zagreb on Wednesday night.
Both United and City have already qualified for the knock-out phases of the competitions they are involved in.
Next up for United and City domestically are games against Everton and Arsenal respectively on Sunday.
