#3 Spring a tactical surprise
Several options have been tried, but it is hard to look past Mata as the Number one choice on the right side.
With Matic and Herrera / McTominay providing cover behind, the United fullbacks have the freedom to rampage forward and provide width. Valencia can hug the touchline, while Mata can play narrow to try and thread passes in behind for Sanchez and Lukaku.
With more key passes (1.7) per game than Martial (1.1), Rashford (0.8) and Lingard (0.9), Mata's creativity can prove the difference in unlocking a tight defense.
Of course, no top team has a rigid inflexible starting 11. United can spring a tactical surprise with the depth of options they have.
Against defensive-minded teams, Pogba can drop into midfield, and Martial can take his place on the left. Against fellow top 4 contenders, Lingard's uncanny ability to find space and greater defensive contribution may make him a better option from the right. Rashford can rotate with Lukaku for the centre-forward position or play from the right in games where the opposition deploys a high defensive line.
Another advantage of having such a depth of options is being able to change the course of a match with substitutions. As a fullback, the last thing you want after 70 minutes is Martial or Rashford running at you with fresh legs.
Talking about fullbacks, there is one in particular at United who should perhaps be playing more...