TMZ Hip Hop linked with Jason still glowing with the euphoria from the night -- the Compton rapper performed his classic "Like Whaaat" track for the Kia Forum crowd, sharing the stage with Black Hippy, Ty Dolla $ign, Tyler, The Creator, Kalan.FrFr, Blxst and many more via DJ Hed and Mustard's sets.

Jason says the entire atmosphere was like a family reunion, he came up in the same Blog Era with Kendrick ... he says the name change reflects his maturity.

Jason was also one of Kendrick's digital hypemen at the height of his clash with Drake but like Roddy Ricch and Big Boy told TMZ Live, the event was bigger than beef ... it bonded Los Angeles communities for the better.

One West Coaster noticeably missing from Kendrick's Pop Out was The Game -- a point that quickly became a trending topic while the event was happening.

Jason tells us he had no idea why Game was M.I.A. but doesn't think it overshadowed the evening ... it's still all love.

Game went live on Instagram Thursday with a lengthy explanation ... he even called Jason and several other hip hop top dawgs out by name for validation.

In a nutshell, Game says all his relationships are solid despite him not being there and also announced he's making "The Documentary Pt. III" album ... you haven't heard the last of him!!!

Jason tells us the same goes for the L.A. gang unity displayed on the Pop Out finale.