City trail leaders Chelsea by six points but have three games in hand and the next week could prove decisive as they face away games against Manchester United and Arsenal.
United have had a disappointing season but have beaten Olympiakos and West Ham United in their past two matches and Toure is expecting a tough challenge.
The City midfielder is also wary of how Arsenal will respond to a 6-0 humiliation at Chelsea which damaged their own chances of becoming champions.
"Both games are important - we must be sharp, clever and very strong," said Toure.
"United are not doing so well but you have to be careful against them.
"Arsenal, after losing to Chelsea, will be hungrier and want their fans to believe in them again.
"It is important we go into those games fully focused and with a lot of confidence.
"We have to do the job, play together and be strong - and any chance we get we will have to take. Then we will see what can happen."
Toure has scored against United in the last two derby games at the Etihad Stadium and is fresh from a hat-trick against Fulham at the weekend, but he is not getting carried away ahead of the latest encounter.
He said: "Derbies are never the same and they will have a lot of desire to beat us.
"We all know United are a fantastic club with a great history and have players that can play at this high level.
"If they play like they did against Olympiakos, we have to be careful."
Whilst conceding that City will try to improve their goal difference at every opportunity, Toure's focus against United is just on getting three points.
He said: "This year will be very close so it's important we score a lot of goals.
"I hope Aguero can come back very soon because he is an important player and we need him.
"Scoring the winning goal against United is not on my mind - the main thing is to win the game. If we can win there it will be very good."