Maresca appears to have picked up where his predecessor, Pep Guardiola, left off with four wins from City’s four opening games of the 2026-27 Premier League season.
Ten men City earned a controversial 1-0 win over Man United last time out after VAR failed to recognise Enzo Fernandez was offside in the build-up to Erling Haaland’s winner.
Despite that hard fought victory, Maresca believes their game against Sunderland "will be the toughest game since the start of the season".
"I know how strong they are, and I have the feeling that on Sunday we need a top performance to beat them, and we need to be 100% to win the game," said Maresca.
"My feeling is, after watching them, is that on Sunday it will be the toughest game since the start of the season.
"If you watch them, you are not surprised (at how well they have done), because you will realise how good they are, how good they are on the ball, off the ball, how aggressive they are, the amount of duels that they win every game."
Sunderland have just one win from their opening four games and sit down in 14th ahead of the game at the Etihad.