The 26-year-old secured his reported £65 million move to the Etihad on deadline day, signing a deal until the summer of 2031.
Ndiaye was handed his first start against newly promoted Coventry, in which a single goal from star man Erling Haaland proved the difference.
Ndiaye expressed his delight with the move, but admitted it was hard to leave former club Everton.
"Very good (game). Started with a win, so couldn't get any better. Felt great, obviously we wanted to win the game. It has been difficult,” he told Final Score.
"Like we said to each other, all the games are going to be hard. The last few days have been really good. Obviously, I am at Manchester City now, so I am happy. Happy the move got done. The lads have been welcoming me very well."