Winning shot from majestic Djokovic? (4)

I believe the answer is:

serb

I'm a little stuck... Click here to teach me more about this clue!

'winning' is the definition.
Although both the answer and definition are adjectives, I can't see how they can define each other.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for serb that I've seen before include "Someone from Belgrade?" , "A European national" , "From Belgrade, perhaps" , "Native of the Balkans" , "One from Belgrade" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.

Connecting...