Despite conceding 16 goals in the Premier League this season, City have also scored more than any other team - 36 - and could return to the top of the table if other results go their way.
“The reality is that we concede a lot of goals. We have to get better. If we concede three, or four goals, two goals every game, it is difficult to sustain it for a long time,” Guardiola said.
“I am concerned about the goals conceded.”