Calls for Jose Mourinho to discard his 4-2-3-1 formation have been echoed by club legend Clayton Blackmore, in an exclusive interview with Tribalfootball.
The Portuguese has come under fire after his side were dominated by Tottenham Hotspur in a 2-0 defeat on Wednesday night.
Despite Mourinho achieving perennial success at Real Madrid, Chelsea and Inter Milan with the same system, critics have now deemed it to be archaic, ineffective and rigid.
Its lack of fluidity has been particularly inhibiting on United's star man Paul Pogba.
The Frenchman was substituted against Spurs after Mourinho lambasted him for not following instructions. His performance was indicative of how the position negates the skills that made United buy him from Juventus in the first place - driving the attack with his dribbling, passing and long-range shots.
And Blackmore, who spent 16 years at United, believes 'the Special One' could be reluctant to change because he doesn't trust his defence.
"The system 4-2-3-1 is the only system I've never played in. I've played in every system or position and I don't get the two sitting midfielders. Chelsea used to do it with one but now you've got two in that area," the 1992/93 Premier League winner told Tribalfootball.
"[Mourinho] drops the centre-midfielder too deep because I think he's worried about the centre-backs. If we played against the top teams I'd be worried if they were good enough to play against the best forwards in Europe.
"I don't like the system we're playing, but he has had success everywhere he went and he brought home three trophies, albeit one was the Community Shield. We've got a fantastic squad of players with players like Pogba & [Zlatan] Ibrahimovic."
After spending close to £150m on transfers in the summer, United expectations were high coming into the season. But the league title chase seems all but lost as Manchester City hold a 15 point lead at the top of the table.
One of United's main problems throughout the season has been their inability to break down opponents who employ deep-lying tactics.
Conversely, City have steamrolled teams with sumptuous attacking football, represented by their 73 goal tally for the season - 24 more than United.
Blackmore argues that United possess a superior squad than their cross-town rivals. But it's the system and lack of effort that cost them when City won 2-1 at Old Trafford in December.
"Against [Manchester] City those two just sat in there," explained Blackmore. "They were playing against De Bruyne and David Silva, and I'm thinking, we're more powerful than them two and we've got Matic and Herrera. If you get them two to man-mark them, they wouldn't get a kick. But we never even got close, they were 20-30 yards off them every time.
"The difference between City and us is that they work hard closing down and we don't, and thats the only difference.
"We've got a better squad than City this season and last season. I've never seen City play as good football and that's because of how hard they work.
"If you watched the Watford game [where United won 4-2], we closed them down and that's what you need to do."
Some may argue that the arrival of Alexis Sanchez could be the impetus for Mourinho to change to a 4-3-3 system, which would allow the Chilean to float between either wing.
But no player will be more affected by a change to Mourinho's system, Blackmore argues, than Romelu Lukaku.
The Belgian, like United, begun the season on fire. He bagged seven goals in as many Premier League games to kick off proceedings, but has scored just four times since.
Blackmore attributes this change to Lukaku's lack of support, which is needed more on the expansive Old Trafford turf compared to the likes of Goodison Park and Stamford Bridge, where the 24-year-old dominated in the past.
"The pitch at Old Trafford you'll find is a lot bigger than Everton, Chelsea and West Brom, and its difficult playing up front on your own," said Blackmore.
"I've played in every position including up front and when you're on your own it's easier to mark with two centre-backs.
"For me, if [Mourinho] tweaked it a bit and tried playing two up front. He did do it when we played Chelsea last year and he put Lingard and Rashford up front and we won 2-0 and they went on to be the champions."
Clayton Blackmore has a new autobiography out titled 'Red, White & Blackmore', you can purchase it by clicking the link here.
Read Tribal's Asif Norat argue why Mourinho should alter his system.