Pep Guardiola remains wary of a Manchester United comeback in their EFL Cup semi-final despite Manchester City's 3-1 win at Old Trafford on Tuesday.
City were largely dominant as Bernardo Silva and Riyad Mahrez scored before an Andreas Pereira own goal in the first half.
Marcus Rashford struck in the second half for United, who will head to the Etihad Stadium for the second leg on January 29.
But Guardiola pointed to United's comeback against Paris Saint-Germain in last season's Champions League – when they recovered from a 2-0 first-leg home loss in the last 16 – as a warning to his team.
"I've played many times against United, not just here, but when I was in Munich and especially Barcelona, and two finals of the Champions League. Of course I have incredible respect for this club and its history," he told a news conference.
"This club helps this Premier League in England and in Europe, to make our game a better place to be. Of course it's an incredible stage to come, an incredible scenario, and to try to play good like we did in the last times we've came here is an honour.
"But that is not three points, that is not done. Last season they lost 2-0 to PSG and after they went to France and you know they qualified.
"Anything can happen in football and I know after what happened in the second half that they are a dangerous team. Hopefully now in front of our people, they can support us like Man United support their team, and again, qualify for the final."
After City dominated the first half, United grew into the game in the second and found a goal through Rashford.
Guardiola was pleased with his side's opening 45 minutes, while praising United's response.
"We played good in the first half, we played really good. In the second half they changed to a diamond [formation] and we struggled more to press and they found [space] behind our holding midfielders," he said.
"[Mason] Greenwood, we could not press because they have two weapons up front with [Daniel] James and Rashford, so it's difficult for central defenders controlling these situations.
"And of course they have pride, they are United so that's normal the reaction they had in front of their people.
"I take note about what happened in the second half for the second leg in three weeks, but it's a good result tonight for us."