Hi Jasmin165. Just to let you know, I'm not a teacher.
I would say that you are correct. "In" would still make sense in spoken English and would refer specifically to basketball practice or a basketball match, but a better word to use if you wanted to say this would be "during". "During basketball" seems bizarre but sometimes in spoken English we refer to sport practice sessions by the name of the sport. For example, "Are you going to basketball tonight?".