Surprising end result chap secured in the Open (11)

'the open' is the definition.
(thesaurus)

'surprising end result chap secured' is the wordplay.
'surprising' indicates an anagram.
'chap' becomes 'he'.
'secured' means one lot of letters goes inside another.
'end'+'result'='endresult'
'endresult' with letters rearranged gives 'unsltered'.
'unsltered' enclosing 'he' is 'UNSHELTERED'.

'in' is the link.