Manchester United coaches Michael Carrick and Kieran McKenna urged Ole Gunnar Solskjaer to change his system before Sunday's sacking.
The Manchester Evening News says the pair were keen for United to adopt a different style of play that was vetoed by Solskjaer.
Caretaker manager Carrick and first-team coach McKenna wanted United to play with a back three sooner and arrest their porous defending.
Solskjaer had intended to change to a 4-3-3 formation in pre-season but United remained in a 4-2-3-1 until the 5-0 drubbing by Liverpool prompted a temporary switch to a back three against Tottenham, Atalanta and Manchester City.
United beat Tottenham 3-0 in the formation but abandoned it before half-time at Atalanta due to injury to Raphael Varane and changed to a back four for the second-half against City as they were 2-0 down.
In Carrick's first match in charge against Villarreal, United started in 4-2-3-1 but changed to 4-4-2 without the ball and 4-3-3 with it. Cristiano Ronaldo, Anthony Martial and Fred all changed roles throughout the 2-0 win.
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