Manchester City manager Manuel Pellegrini has warned that things will only get more difficult for the club after the international break as Premier League fixtures begin to be juggled with Champions League and domestic cup commitments.
City are the only team with a 100% record from their first four league games of the season, and are yet to even concede a goal as they enjoy a three-point gap at the top of the table.
However, the Chilean insists that the true test of his pace-setting side will come when domestic football returns after this weekend's international break.
"Football changes so easily," he told The Mirror. "You cannot know what will happen in the next month. Now we have an international break. On the one hand, it is good to stop, because we have a lot of injured players. On the other hand, we are playing well, so we want to continue.
"For the opening month, we have played just one game a week, but when we come back, the Champions League starts, and the Capital One Cup starts [for City], too. So we will be playing eight games each month.
"There are a lot of things that can make football change. That is why it is important to start well and to know why we are playing this way."
City can open up a minimum of a four-point gap just five weeks after the start of the season if they beat second-placed Crystal Palace at Selhurst Park on Saturday, September 12.