Manchester City striker Sergio Aguero has acknowledged that his side will have to be at their "very best" to beat Manchester United at Old Trafford on Sunday.
The local rivals will do battle in the Manchester derby with just one point separating the two sides in the Premier League table after the Red Devils moved above City in the last round of games.
Despite five consecutive league wins going into the weekend, United have been inconsistent in terms of performances for much of the season, but Aguero is fully aware of the threat they can pose when on form.
"They are a team with a lot of great individual players, who can form an incredible unit when they work well together. But this season that has not always been the case," the Argentine told Sky Sports News.
"Some matches they don't seem to play at the maximum, with the attacking qualities that they have in the team. But then in other games, they have really shown that those qualities, so they are a bit unpredictable.
"We know we will have to be at our very best to beat them - there's no doubt about that."
Manchester City have enjoyed great success in the derby in recent years, winning the last four meetings between the two sides.