Initially explosive start around F1 (2,5)
I believe the answer is:
at first
'initially' is the definition.
(synonyms)
'explosive start around f1' is the wordplay.
I cannot quite see how this works, but
'start' could be 'first' (synonyms) and 'first' is found within the answer.
The remaining letters 'at' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for at first that I've seen before include "Originally" , "In the beginning, to start with" , "In the beginning, initially" , "To begin with" .)