The most common and most likely answer to this crossword clue is the 9 letter word GARLANDED
I've seen this crossword clue in The Times
G
A
R
L
A
N
D
E
D
Buddy explains!

The straight part
We know that "crowned as winner" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case crowned as winner = garlanded.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GARLANDED mean?
GARLANDED verb- To deck or ornament something with a garland
- To form something into a garland