You had a crush on Kageyama so you always went to watch him when he played a match.

On one match, he gave his sweater to another girl, so you got jealous and started cheering up a guy from the other team.

But then the girl who had Kageyama’s sweater gave it to you and said that he told her to give it to you.

You got embarrassed and looked at Kageyama, who was jealous because you were cheering for a guy from the other team and not for him.