Speaking on the eve of City's Champions League Group C opener against the Germans at the Etihad Stadium, City manager Guardiola stressed the need for his side to improve in all areas.
This came despite City earning widespread praise for a lot of their play in Saturday's derby victory over arch-rivals Manchester United in the Premier League.
Schubert now needs to get the better of Guardiola to ensure his team get off to a good start in a difficult group that also includes competition favourites Barcelona and Scottish champions Celtic.
Schubert said at his pre-match press conference: "The season has only just started but I think their record in the English league speaks for itself and the results and the way they are playing speak for themselves.
"Manchester City this season have a very good chance of winning the title
That is why Pep Guardiola has come here.
"They are trying to soften expectations but they are one of the best teams in the world, have spent a lot of money and have one of the best coaches there is on the bench."
Schubert's side, who are facing City in the group stage for a second successive year, took four points off Guardiola's Bayern Munich in the Bundesliga last season.
He hopes they will go into the game at City in the same positive mindset even though they were beaten at the weekend at Freiburg.
He said: "We want to be brave. Football is a great game, it is fun, and we always go into games with a feeling of being up for it rather than thinking we are going to lose.
"We will do the best we can, comparing ourselves against the best and see what happens. We need to push ourselves all the way. We are playing a very strong team and we are aware of that."
Source: PA