City boast the best defensive record in the Premier League and have not conceded in Europe since Luis Diaz scored for Porto in the opening game of the group stage.
But ahead of the second leg of our last 16 tie against Borussia Monchengladbach, Guardiola warned his side cannot take our fine form at the back for granted.
“Definitely so important, in the Champions League,” he said at his pre-match press conference.
“What we’ve done in the past is good but doesn’t mean it will happen tomorrow.
“Every game is different, let’s try to minimise the mistakes, we know how they punish us.”
The manager also discussed his squad rotation policy, Bernardo Silva’s form and Gabriel Jesus and Sergio Aguero’s partnership.
Watch the full press conference in the video above.