The Brazilian came on in the second half at the Etihad, after Erling Haaland and Phil Foden had effectively sealed the three points for City during a 4-0 first half blitz.
Casemiro, a £60m signing from Real Madrid in mid-August, is yet to start a Premier League match since his arrival from the Spanish capital.
Scott McTominay has been keeping the Brazil international out of the starting line-up with a string of impressive performances but he underwhelmed as City reasserted their dominance over their rivals on Sunday.
Ten Hag has been accused of getting his tactics wrong on Sunday, with the Dutchman sticking with a midfield pairing of McTominay and Christian Eriksen rather than fielding either Casemiro or Fred.
But Casemiro is set to start on Sunday and could even start in Thursday’s Europa League clash against Omonia.
‘On the day we signed him [Casemiro], we started to win and it’s about the team,’ saidTen Hag.
‘The team is doing really well, it’s not against Casemiro, it’s for, in this case, Scott McTominay.
‘He performed great in the team and then we get into a run, but I’m sure it will be important for us in the long and short-term.
‘He [Casemiro] will find himself in the team but it has to come in a natural way.’
Really when someone doesn’t understand afterward its up to other people that they will assist, so here it occurs.