The Portuguese manager's focus on three at the back in pre-season mean it is likely he will start the campaign with that formation at Old Trafford.
Premier League 2017/18 preview: Defensive tactics vital to Mourinho and Manchester United's title tilt
When Louis van Gaal left United after two pretty underwhelming years, he maintained that while his tactical ideas were sound, he did not have the players available to implement them.
Van Gaal started with a 3-5-2 formation which initially looked clinical. United beat Real Madrid 3-1 in a friendly watched by 109,000 in Michigan, with Ashley Young, one of the side’s best players stating: “It’s a new system and a new way to play but everyone has adapted to it and understands the manager’s philosophy.
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"The formation gives us more time to play and more space and we’re all enjoying it. We’ve just played against the European champions and even though it’s pre-season I think we deserved to win.”
United are playing against Real Madrid again next week, this time for real in the European Super Cup, where the Uefa Champions League winners and Europa League winners will meet in Skopje, Macedonia.
It is United's first competitive game before their Premier League campaign starts next Sunday against West Ham United.
Van Gaal abandoned his three at the back system and experimenting after stuttering start to the 2014-15 season and a 5-3 defeat by Leicester City which left United 12th.
Before Sir Alex Ferguson departed in 2013, he saw United’s future as playing like Barcelona, with smaller, technically excellent players pressing and dominating play. Van Gaal came in with his own ideas, but moved away from his original intentions.
Jose Mourinho may have said that his players needed to be reprogrammed after two years of Van Gaal, but he has been experimenting with the same 3-5-2, which switches to a 5-3-2 when United defend, just like Van Gaal.
The team get their width from the full-backs. Mourinho used three at the back for an hour in United’s final pre-season game, their sixth win in seven matches, against Sampdoria in Dublin on Wednesday.
If he is not going to start with three at the back against Madrid next week, then why trial the system so thoroughly?
United, whose players are enjoying a couple of days off before they fly to Macedonia on Monday, underwent a positive pre-season.
Romelu Lukaku, Victor Lindelof and Nemanja Matic are settling well. Mourinho’s priority is to bring a left-sided winger in, one who can give him a few less frustrations than the talented but inconsistent Anthony Martial, though if there’s any area of concern for United at present then it’s in defence.
Marcos Rojo, a disappointment in that Leicester game, improved so much last season that he would have been a contender for player of the season had he not picked up a serious injury towards the end of the season.
He will be absent until later on in the year, left back Luke Shaw is also injured and Lindelof looks like he may need some time to settle in England. He’ll get it.
Eric Bailly has emerged as the key central defender, though he’s suspended from the game in Skopje. As is Phil Jones, who has also had a good pre-season, though United could appeal.
United are likely to look to a three of Chris Smalling, Lindelof and Blind next week, with Antonio Valencia and Matteo Darmain as the full-backs.
Demetri Mitchell, a 20-year-old defender is very highly rated, as is another local boy from the youth academy, Axel Tuanzebe, plus Dutch youngster Timothy Fosu Mensah. Playing any of them against Real Madrid in a final remains a risk for the pragmatic Mourinho.
United’s defence is an immediate worry, but the team are improving and the spirit among the players is excellent and far removed from the anxiety which prevailed under Van Gaal. The players really do believe in their manager and those who watch them closely can see why.
“We’re progressing,” said former defender David May, who has watched every pre-season game.
“The three signings will improve the team. I think we need one more, someone who can play on the left. It depends how Jose Mourinho is going to set up. He’s played three at the back while we’ve been away and it has worked really well at times.”
United will hope it works well in the Super Cup final, but progress in the Premier League will be a truer barometer of how United are doing under Mourinho as they bid for a first title since 2013.
“I think we’ll win the league this year,” said Paddy Crerand, a member of United's 1968 European Cup winning side.
Van Gaal never earned such optimism; no matter what formation he played.