What we're going to see is that Manchester United, over a period of time, will be back to where they were under Sir Alex Ferguson: perennial title contenders that win plenty of trophies. Especially when you look at the signings that Mourinho has made and the winning mentality that he brings. I think you're also going to see Manchester City go to that kind of level with Pep Guardiola.
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It is going to be difficult for the other teams in the Premier League to stay with them. For all that Antonio Conte brings at Chelsea, he's still got a fair bit of work to do with that squad.
I'm yet to be convinced that Tottenham can challenge as strongly this season as they did last time out.
Liverpool are still very much a work in progress, and I think Arsenal, unless they can make significant signings, are going to be left behind.
So the way is clear for United and City to dominate at the top of the league this year.
You've got to look at why the fear factor is back at Manchester United and it's because they've got a proven winner in charge. Mourinho has the personality to dominate, garners instant respect from the players and is a tremendous recruiter.
The key to Ferguson's teams of the past is that they always had a spine of goalkeeper, centre back, central midfielder and striker. The first thing that Mourinho has looked to do is add to the keeper they have with a dominant central defender, midfielder and striker in Eric Bailly, Paul Pogba and Zlatan Ibrahimovic respectively. Once you’ve got that in place, allied to Mourinho's strengths, you're starting to get the package back at Old Trafford.
I think there was less for Guardiola to do at Manchester City, but the mental impact he has on his own players will have a huge effect. I got the impression last season that when Manchester City got to the semi-finals of the Champions league against Real Madrid, they felt they had achieved enough. I commentated on both legs and I don't think they had the mental strength to reach the final and I think the key for Guardiola is the psychological impact he has on his own players when they get to that stage of the Champions League.
They are two very good fits at the respective clubs they are at.
Darren Fletcher is a commentator for BT Sport