There is a flaw in Jose Mourinho’s argument that the difference between Manchester United and Manchester City is money.

If Pep Guardiola was in charge of the United squad I believe they would win the title.

Rewind to the start of this season and assess the head-to-head qualities of the United and City squads. Player-for-player, which would you argue was superior?

Was Ederson considered better than David De Gea? Were City’s centre-backs Nicolas Otamendi and John Stones preferable to Eric Bailly and Phil Jones? Did United fans want Fernandinho or Nemanja Matic?

United broke the world transfer record to sign Paul Pogba, and then made Romelu Lukaku the most expensive Premier League player of last summer. Which English clubs made bigger statements of intent?

Mourinho complained this week that United can't compete financially with City credit: Action Images

How many United or England fans would have swapped Marcus Rashford for Raheem Sterling a year ago? And when Anthony Martial first arrived from Monaco, was his reputation greater than that of Leroy Sane when he joined City?

Although he was signed before Mourinho’s appointment, Luke Shaw was a £30 million full-back – more expensive than City striker Gabriel Jesus. The United manager’s complaints about the value of the squads do not add up.

We can go on throughout the respective lists. Where Mourinho sees players unable to execute his tactical blueprint, I believe Guardiola would have taken a different approach with a squad Mourinho believes needs reinforcing.

Even now, it is the United squad that has the most expensive ‘superstars’ – or certainly those with the greater reputation when they joined the club. Henrikh Mkhitaryan, Pogba and Lukaku delivered elsewhere prior to moving to Old Trafford. Have they improved under Mourinho? That is the troubling question for the United manager. It is starting to sound like he has no patience or will to make what he has better.

Luke Shaw cost more than Gabriel Jesus credit: AFP

City's transfer policy does involve lavish spending, but some fees have often been more eye-catching than the names. Of Guardiola’s signings only Ilkay Gundogan and Benjamin Mendy – players absent with injury for much of their time in Manchester – arrived as fully-established 'stars' elsewhere.

City are ahead this season because Guardiola has developed players rather than expected ready-made talent to instantly deliver. Mourinho has increasingly come to rely on more experienced, established performers. If you want to evolve a club or a team, you don’t call Mourinho. He is a coach who navigates his way to silverware with teams that have the raw materials – something he has already achieved at United with two trophies in his first season. His reputation as a world-class coach is based on his ability to find a way to win. His legacy will be elevated if he returns to what made him so outstanding during his first spell at Chelsea when guiding players such as John Terry, Frank Lampard – who he inherited and made better - and Didier Drogba who he signed and made world-class after an indifferent first season at Stamford Bridge.

If Mourinho was coaching the Manchester City side they would not be playing the style of football we are seeing today. If there is a symbol of that look no further than Kevin De Bruyne, a player Mourinho coached at Chelsea but then sold.

Kevin De Bruyne has excelled under Guardiola having left Chelsea when they were managed by Mourinho credit: Getty Images

I have heard all the arguments about how De Bruyne – just like Mo Salah - was not so developed at Chelsea during the Mourinho era, and Chelsea did not suffer given they won the title twice in three years after selling him. But would other managers have discarded such a talent, or would they have found a way to nurture it in the long-term interests of the club? It is hard to believe Guardiola would have managed De Bruyne on a daily basis at a young age and not seen what he might become.

Where Guardiola is delivering in the short-term with an eye on further development, Mourinho is now about the instant hit. Players who may excel in two or three years time do not seem to be of interest as he rarely hangs around at a club to reap the benefits of their progress.

The financial power at City enabled Guardiola to create a team in the image of his great Barcelona side, but many of those he has improved were at the club. De Bruyne was an excellent player before Pep’s appointment. Now he is the best player in the Premier League. David Silva has been revitalised with a change of position in central midfield. Who else would have put him there? Would Fabian Delph or Otamendi be the players they are under Mourinho? Do not forget Guardiola also inherited an ageing squad and had to ship out and replace plenty of players.

Pep Guardiola's City have been sensational this season credit: Getty Images

The concern for Manchester United is Mourinho is working through his repertoire of gripes. You would normally expect this in year three or four after he has won at least one Premier League title. I’ve always loved hearing Jose’s press conferences – even as a player and rival I wanted to tune in - but I much prefer it when he is being mischievous rather than prickly. When he picks fights with his own players, supporters and board members it becomes a tired act and sounds like he is making excuses. Everyone becomes exhausted by the agitation. Usually, it ends one way.

In the past he might have earned sympathy. Not now. Not at one of the world’s richest clubs when you have outspent most of Europe and the only way to keep up with your greatest rival is to match him on the training pitch and with shrewder management.

That is what separated Sir Alex Ferguson from the rest. For all his success at United when he could bully rivals in the transfer market, it was Ferguson's latter years when Chelsea and City were capable of outspending him that impressed me most. He not only kept United competitive, but ensured they were title winners because of their brand of football. Since Ferguson retired in 2013, United have spent in greater excess than when he was there. They have paid over £600 million on new recruits under David Moyes, Louis Van Gaal and Mourinho.

This shows the biggest difference between City and United this season is nothing to do with money.

Guardiola is breaking records. Mourinho is starting to sound like a broken one.