For me, the most under rated player in United has got to be Cleverly. 

Busquets and Pedro

Josh McEachran

Oriol Romeu

Afelley

Coentrão

@ramaboy For sure, forgot about him!

Kaka (recently people say that he lost his touch .... but mind you .... he is Ricardo Dos Santos Kaka)

Raphael Varane.

To an extent Higuain ( though he is good ) but I think him underrated because he is compared to Benzema who is considered better than Higuain but I feel Higuain has better dribbling and ball control than Benzema.

^ in my opinion Higuain is better than benzema.. Has more techinque,better finishing(what goals has he scored) and better positioning.. Benzema is faster and has better dribbling. If Someone is Underrated at Madrid is Coentrao nobody notices him because there is Marcelo despite the fact that he is a better defender. Marcelo more skillful(either coentrao is but not it that way).
Also in every other team except for madrid and barcelona Coentra would have been the first choice for the starting eleven because Real Madrid Has always the ball and they dont need to defend so much. Also Marcelo has a better partnership with Cristiano..
That's just my opinion ! :P

That is very, very true about Coentrão, Don. But I think Coentrão has a really good partnership with Ronaldo and the other players as well - except he's just more quiet than Marcelo. :)

Arteta

@don; thats what I meant ... higuain is better in many aspects than benzema but many people question his game and prefer benzema. Thats the reason him getting a bit sidelined this season.

Not sure about Coentrao ... Mou has prefered him in Clasicos and several other fixtures. He has got his chances and has proved his worth. The reason why he got sidelined is that Madrid play attack cum counter football where Marcelo can act as a attacking wing support ... something Coentrao lacks, but that doesnt mean he is underrated, its just that his style is different which doesnt match Madrid gameplay . There is a reason Tottenham are monitoring him for next summer. Again my opinion !

GUARIN

Underrated by Arsenal fans: Szczescny & Ramsey
Underrated by Non-Arsenal fans: Sagna (one of the top 5 RBs in the world IMO) & Arteta (has completely re-invented himself at Arsenal).

@naman93
thats why he prefer coentrao to marcelo against Barcelona! because he is a better defender..

prefers*

Exactly, Don. When Real play Barca, Real don't have as much possession against them as they would've had against other 'weaker' teams they usually face in the league. Good observed. That's simply why Mourinho uses Coentrão in an El Clasico.

Messi, and i'm not joking! This guy is so underrated, he's the best players in the world and maybe one of the best players in the whole football history but there still are people who compare him with Cristiano. I'm sorry if i'm being a bit agressive but that's true, peace, Nico.

Of course people compare him with Ronaldo. You can't get without it. Both are over-performing all the time. But Nico, to take it for granted that people shouldn't compare those two is ridiculous.

have to agree with devilz, Tom Cleverley.

Ramsey