Document from Manchester United's vault picked up (10)
I believe the answer is:
manuscript
'document' is the definition.
(I've seen this before)
'manchester united's vault picked up' is the wordplay.
'manchester united's' becomes 'Man U's' (Man U is a common nickname for the team).
'vault' becomes 'crypt' (I've seen this before).
'picked up' indicates a 'sounds like' (homophone) clue.
'crypt' is a homophone of 'cript'.
'manus'+'cript'='MANUSCRIPT'
'from' is the link.
(Other definitions for manuscript that I've seen before include "Handwritten document" , "Handwritten text" , "text awaiting publication" , "Document written by hand" , "Original or copy of document" .)