Manchester City are currently on a 23-game unbeaten streak and have the chance of completing a historic treble after the midweek Champions League victory over Real Madrid.
Grealish believes Man City are unstoppable
"I don't think many teams can do that to Real Madrid but when we're all together and playing, especially at home, we feel unstoppable," Grealish said after Wednesday's victory.
Guardiola disagrees
While his manager Pep Guardiola was equally delighted with the victory, he made a point to call for caution, particularly over Grealish's 'unstoppable' comment.
"I don't like that, no," Guardiola said. "Every team is stoppable if you do what you have to do. It's nice the players feel that, but football can change from one game to another.
"You have to stay calm. I would like to give the players two days off, but I cannot give them one because the Premier League is there."
Manchester City are next in action against Chelsea and could lift the Premier League trophy with a victory or with a draw, depending on the outcome of Arsenal's game at the weekend.