Pep Guardiola accepts success does not last forever and says he cannot guarantee Manchester United won't overtake Man City while he is in charge.
New Manchester United minority co-owner Sir Jim Ratcliffe vowed recently that he and his Ineos team are working to knock City and Liverpool 'off their perch' in the next three years.
Here in the present the gulf between the teams is profound. Erik ten Hag's side head to the Etihad Stadium on Sunday 15 points adrift of their rivals in the Premier League and find themselves at risk of missing out on Champions League football next season.
But speaking ahead of Sunday's derby day, Guardiola isn't as down on this 'incredible' United team as many critics are and believes success is cyclical.
'The 80s was Liverpool, 90s was United and now we have won seven Premier League's in the last 11 or 12 years,' Guardiola said.
Pep Guardiola (L) has suggested Man City's success won't last forever ahead of their clash against Erik ten Hag's Manchester United
The Spaniard has helped City dominate English football by winning five titles since 2017
'It has happened. In 50 or 60 years, there has never been one country where one team always dominates.
'We will try to extend this as much as possible for many years.'
Jose Mourinho's second-placed finish with United in 2017-18 is the closest they have come to title contention but Guardiola feels sorry for his peers in the Old Trafford dug-out in trying to restore the club to its past glories.
'I would say at big clubs you have to win and win, not just United,' he said.
'You have to [win]. It's not easy for United to come from incredible success with Sir Alex [Ferguson] and that is not easy. I can understand it.
'Before in England, big clubs had more patience but today everyone has a lot of pressure.'
He reiterated that while his side were currently dominating, United had bossed English football during the 90s and noughties - and opened the door to them rising up again
Guardiola said United still had 'incredible quality' despite 15 points between the two teams
Jack Grealish, who was emotional at having to come off injured against Luton this week, is not going to be fit enough to play, but Guardiola is relaxed at heading into what is a crucial game for both sides.
Asked how he handles the Manchester derby after years of experience, he said: 'Be calm, relax, don't focus on many things but just about tactics and what you have to do to beat them. Don't talk about emotions because they will be there.
'For United to go to Wolves and beat them and have the quality to beat Aston Villa a few weeks ago, they have incredible quality. From one action, they create something special.
'When they play good, they are really good and are able to win games. We are in March and they just lost one game this year - last week at home [against Fulham]. Prepare the game tactically to try to get three points and continue to be up there.'