Predicted loser grounded unexpectedly (8)
I believe the answer is:
'predicted loser' is the definition.
'underdog' can be an answer for 'loser' (underdog is a kind of loser). I'm unsure of the 'predicted' bit.
'grounded unexpectedly' is the wordplay.
'unexpectedly' indicates an anagram.
'grounded' is an anagram of 'UNDERDOG'.
Can you help me to learn more?
(Other definitions for underdog that I've seen before include "One with little status" , "Unlikely Victor could be" , "outsider" , "One expected to lose" , "Less fancied competitor" .)