Como obter o jogador de pontuação máxima de cada grupo usando SQL?

select group_id, player_id
from (
    select
        p.*,
        row_number() over(
            partition by p.group_id 
            order by case 
                when m.first_player = p.player_id then m.first_score 
                else m.second_score 
            end desc,
            player_id
        ) rn
    from players p
    inner join matches m
        on m.first_player = p.player_id or m.second_player = p.player_id
) x
where rn = 1

| group_id | player_id |
| -------- | --------- |
| 1        | 65        |
| 2        | 20        |