Jose Mourinho was at his acerbic best when he slapped down TV pundit Frank De Boer for criticising his management of striking sensation Marcus Rashford this month. The Manchester United boss pulled no punches after De Boer said it is a pity that Rashford plays under the Portuguese, who is famed for his conservatism. Mourinho branded De Boer “the worst manager in the history of the Premier League”, ridiculed his record of seven defeats in seven games and said the most important thing is simply to win. It was TV gold, but it hinted at a growing frustration at having to defend his methods in public.

Scrutiny has intensified on Mourinho due to the dismal nature of his team’s Champions League exit at the hands of unfancied Sevilla. United only scored once in 180 minutes of football and lost 2-1 on aggregate against a team well outside the top four in Spain. Meanwhile, the noisy neighbours are playing a scintillating brand of football and Pep Guardiola’s men have opened up a 16-point lead over United, with eight games to go.

City have scored 27 more goals than United this season, despite conceding three fewer, and many pundits claim that the visionary Guardiola has left Mourinho behind in terms of tactics and approach.

United have also scored 15 goals fewer than third placed Liverpool, who have thrilled neutrals with their attacking exploits this season. They now face a battle for the runner-up spot with Jurgen Klopp’s men, and fans are uneasy about being compared negatively to their two greatest rivals. There is said to be a United way of playing – remaining on the front foot, taking risks and eschewing a brand of attacking, free-flowing football that was nurtured under Sir Alex Ferguson – and right now United are not playing it. City embody those traits, as do Liverpool, and even Spurs under Mauricio Pochettino have looked more exciting going forward than United for much of the season.

United are clearly progressing under Mourinho, who won the EFL Cup and Europa League last year and has finally got them back in the top four picture after years in the wilderness. But for many fans that progress has come at too high a cost. Parking the bus is a phrase invented for Mourinho teams, so his tactics should not come as a surprise to anyone. His latest media strategy has been to write off doubters as lacking brains, arguing that his team are in a transitional period. But the unrest is growing and it has certainly spread to some of the players.

It is hard to imagine an attacking player wanting to play for Mourinho rather than Guardiola or Klopp right now. Man City stars and Liverpool stars typically enjoy more freedom to express themselves, track back less and enjoy more chances in front of goal. Mourinho has an embarrassment of attacking riches at his disposal – Rashford, Alexis Sanchez, Jesse Lingard, Anthony Martial and Romelu Lukaku, yet you could argue that Mourinho’s tactics are stifling his star players and stopping them from shining. Check the Premier League top goalscorer odds and you will see a straight fight between Liverpool’s Mohamed Salah and Man City’s Sergio Aguero, now that Tottenham’s Harry Kane is injured, and Lukaku and co are nowhere in sight.

The Manchester derby on April 7 will once again shine a light on the issue, not least because it could be the game in which City clinch the title. They have already won at Old Trafford this season and they are the clear favourites with the bookmakers to complete the double over the United. It will be a wistful occasion for Sanchez, who came very close to joining City last summer. Instead Arsenal pulled the plug on the transfer and instead he joined United in January. Since then he has flopped, having failed to adapt to Mourinho’s tactics thus far, and he has simply watched on as City have pulled further away.

Sanchez isn’t alone, with Paul Pogba also struggling for form in recent months. The Frenchman was a revelation under Antonio Conte and Massimiliano Allegri at Juventus, and he proved such a devastating force that it convinced United to break the world transfer record to bring him back to the club. Yet after a brilliant start he has gone well off the boil in 2018.

Mourinho’s tactics are certainly stopping some of his players from reaching their full attacking potential. He has never been a risk taker and he always demands his stars track back, so they are never going to flourish as they would under Guardiola or Klopp, or even under Arsene Wenger. That is not necessarily a bad thing, as long as they are winning games, because winning is all that matters for Mourinho, and fans and players love celebrating silverware. The Portuguese’s approach has yielded 25 trophies, the sort of haul that Klopp, Pochettino or Wenger could only dream of, so you cannot argue with his pedigree.

Some attackers have done well under him, mainly combative forwards like Didier Drogba and Diego Costa, but also creative talents such as Wesley Sneijder, Deco, Arjen Robben and Joe Cole. But these players were willing to adapt to his system, and others have rebelled. More attackers could grow disillusioned under Mourinho, who values defensive stability, power and discipline above artistry and risk-taking. They will not care too much if they are winning trophies, but if United find themselves usurped by City, Liverpool and Spurs over the next year or two, it could be time for the club to bring in someone more attuned to the United way.