Back-to-back Premier League defeats to Newcastle and Everton saw Chelsea drop to sixth in the standings, one point off fifth-placed Liverpool and seven off fourth-placed Aston Villa.
Rosenior is aiming to claim his second Premier League victory from his last seven matches as pressure grows on the Englishman, whose main priority is climbing into the Champions League spots in the final seven games of the campaign.
Fernandez won't face Man City
Firstly, he confirmed that Enzo Fernandez will miss the clash against City after he "crossed a line" with comments he made about his future, which included flirting with a move to Real Madrid.
“We had a really good conversation. He's apologised to me, the club. We will deal with that after a massive game on Sunday," Rosenior said.
"You can't overstep the punishment for the mistake. I made a decision. What I want for Enzo is for him to go on and have an amazing career. He won't play on Sunday.
"There are certain values and cultures that I believe in that make the club stronger if you get them right."
Rosenior confident his side can pick up three points
Chelsea are still without the injured Filip Jorgensen, Levi Colwill, Reece James, Trevoh Chalobah and Jamie Gittens as Rosenior rotates his side who he believes can cause serious damage to City.
"I don't have a big enough ego not to respect people. Pep (Guardiola) has influenced everyone in football. He's an unbelievable coach with an unbelievable career but I want my team to show what they're capable of on Sunday.
"He's won trophies, he's invigorated the team. He also had time to put a style together.
"We need to not switch off or make mistakes because City will punish you."
Can Chelsea beat City: “Of course we can. We're a very good team, we've gone through a difficult run. When I analyse the games we have had, we've caused every team problems but not had the results for that.”