Card game to stimulate tense F1 driver (6)
I believe the answer is:
piquet
'f1 driver' is the definition.
(Nelson Piquet)
'card game to stimulate' is the wordplay.
'card game' becomes 't' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'stimulate' becomes 'pique'.
't' after 'pique' is 'PIQUET'.
'tense' acts as a link.
This may not be correct. It may be part of another bit of the clue.
(Other definitions for piquet that I've seen before include "Card game with 32 cards" , "patrol" , "Card-game with 32 cards" , "Racing driver" , "Card game for two" .)