Sauce found in vessel revolting (7)
I believe the answer is:
ketchup
'sauce' is the definition.
(ketchup is a type of sauce)
'vessel revolting' is the wordplay.
'vessel' becomes 'ketch' (ketch is a kind of vessel).
'revolting' becomes 'up' (rising up or revolting).
'ketch'+'up'='KETCHUP'
'found in' acts as a link.
(Other definitions for ketchup that I've seen before include "Sauce made largely of tomatoes" , "Piquant sauce, often tomato based" , "Red sauce" , "Relish" , "Condiment" .)