American dressing winning yacht, back-to-front (7)
I believe the answer is:
ketchup
'yacht back-to-front' is the definition.
I can't tell whether this defines the answer.
'american dressing winning' is the wordplay.
'american dressing' becomes 'ketch' (I can't justify this - if you can you should give a lot more credence to this answer).
'winning' becomes 'up' (eg being up at half time in football).
'ketch'+'up'='KETCHUP'
Can you help me to learn more?
(Other definitions for ketchup that I've seen before include "Sauce made largely of tomatoes" , "Spicy tomato sauce" , "Red sauce" , "Relish" , "Condiment" .)