City were 3-1 winners in the Danish capital thanks to goals from Kevin De Bruyne, Bernardo Silva and Phil Foden.
That means we have a two-goal advantage for next month’s return leg at the Etihad Stadium and have set an English record of nine straight victories in the Champions League.
FC Copenhagen 1-3 City | Match report
Having seen Copenhagen come through a group including Bayern Munich, Galatasaray and Manchester United, Guardiola believes his side’s victory should not be underestimated.
“I know how difficult it is,” he said.
“When people think it is easy, that makes it easy but it is not. Ask Bayern Munich and Galatasaray and Manchester United how hard it is.
“They are a really tough opponent. We played really good.
“My job is to warn the players and tell them the attributes we will need and they proved it and felt it. We behaved with the correct personality and patience and everyone was at top, top level.
“You don’t make this level in last-16 without it. Hopefully we can make the next step and go to the quarter-finals.”
After Bernardo’s deft finish just before half-time it looked for much of the second period like there would just be a one goal difference between the sides.
However, Phil Foden’s late one-two with De Bruyne and powerful hit sealed a third on the night and some breathing room for the return fixture in three weeks.
While Guardiola is not resting on his laurels, he acknowledged the importance of that added time finish from our Academy graduate.
“The third goal helped us a lot to manage the game more there [at the Etihad],” said Guardiola.
“We know each other better now so they will prepare something but we will prepare something too.
“The first game of the last-16 is always dangerous but the players behaved and performed really good again.”
With the Parken Stadium famous for its atmosphere and Copenhagen strong at home during the group stage, Guardiola was keen to see his players take the sting out of the game early on.
Having studied our opponents since the draw was made, he knew the Danish champions would not try to come at us from the first minute.
“As a team they don’t come to take the ball - they come to defend the space,” said Guardiola.
“They wait for you to lose the ball. The players don’t press, they defend the space.
“That’s why you have to be so patient, move them left and right attack them and don’t concede transitions.
