But Ederson gifted the ball straight to Copenhagen with a poor clearance and Magnus Mattsson took full advantage with a fantastic strike.

Bernardo Silva put Manchester City ahead again just before half-time with a clever flick after a ball from De Bruyne deflected through to him.

De Bruyne and Erling Haaland had further chances to add to the lead after the break and, although City were not quite at their attacking best, they ensured they left with a two-goal cushion thanks to Phil Foden's late strike.

"The biggest players appear on the biggest stages," said Guardiola on TNT Sports. "It's the hour of truth. We started well. We have to do our job and finish it.

"I'm just really pleased for the result."

Manchester City will host Copenhagen in the second leg on Wednesday, 6 March.

Man City 'patient in the right moments'

This was Copenhagen's first game in two months after football in Denmark was paused for a winter break but Guardiola had warned before the game that they would still not make things easy for his side.

The Danes had beaten Manchester United 4-3 at the Parken Stadium in the Champions League group stage back in November, and also held Manchester City to a goalless draw there in 2022.

Guardiola's side started like a train, but while they failed to sustain that momentum they did have plenty of chances to win by a greater margin.

However, ex-Liverpool goalkeeper Kamil Grabara played a key role in limiting the visitors to two goals, making good saves to deny Ruben Dias early on and Jeremy Doku in the second half.

But in the closing stages, the visitors stepped it up again to ensure they got a healthy advantage for the second leg and secured it when Foden drove in from De Bruyne's cutback.

"Today was perfect," Guardiola added. "They were patient in the right moments. Really good.

"I'm really proud of the team. The third goal helped us a lot. Hopefully we can finish it off at home and go to the next game."

Guardiola waits on Grealish injury

Jack Grealish was making his first start since the FA Cup third-round win against Huddersfield on 7 January

Manchester City's early momentum was clearly disrupted by the early departure of Jack Grealish to injury.

The England forward was making his first start in six games but pulled up with what appeared to be a muscle injury after challenging for the ball with Diogo Goncalves.

Grealish, who missed three games in September with a hamstring injury, was then taken off in the 21st minute and City will be hoping the issue is not as bad as it initially looked.

"It looks like a muscular [injury] for Jack Grealish," Guardiola said.

"It is a pity. He helped us to play at the right tempo. He felt it when he rolled on the grass."

Guardiola also revealed Silva picked up an injury, adding: "Bernardo took a big knock on the ankle. Hopefully it is not a big issue, but we will see."