Displaying comments on pages distinguished by GET IDs

As far as WordPress is concerned, the individual match pages are the same page, the presence of your GET var is meaningless to WordPress.

option 1 – make the individual matches unique objects, such as additional pages or a custom post type.

option 2 – hook comment_post and update_comment_meta when a comment is submitted to store the associated match id the comment was entered on as meta data. you’d then filter comment output in your wp_list_comments callback to only display comments with meta value that matches the current match.