A haven in Monaco, as I suspected (5)
I believe the answer is:
oasis
'a haven' is the definition.
(I know that haven can be written as oasis)
'in monaco as i suspected' is the wordplay.
'in' indicates a hidden word.
'OASIS' can be found hidden inside 'monaco as i suspected'.
(Other definitions for oasis that I've seen before include "Pop group" , "British band" , "Feature of desert" , "Britpop group" , "Fertile tract in a desert" .)