One of the hottest rappers in the game named a song after Derek Fisher ... and you know who's stoked about that??
DEREK FISHER .. 's kids, 'cause the ex-Lakers star says Gunna's tribute gave him MAJOR cool points with the youngins in his house.
For those who aren't hip to the College Park spitter, Gunna is one of the biggest names in the industry right now ... and his collab mixtape with Lil Baby, "Drip Harder," is widely considered one of the top projects of 2018.
Gunna's follow-up, "Drip or Drown 2" just dropped last week .