TMZ has obtained video that was taken early Saturday morning in Chatsworth, near Blueface's home. We're told this fight you see here on camera followed what eyewitnesses claim was a bum rush attempt by Chrisean on Blue ... dropping in on him at his house.

You see, we're told Blueface was throwing a party at his crib to ring in his 26th birthday (Friday) ... and that Chrisean crashed the shindig in an effort to pull him away.

What you see here is what we're told happened shortly thereafter ... it seems Blueface was trying to get away in his own vehicle -- with a gaggle of people following him, including Chrisean -- and it all erupted in a massive brawl on the street down the block from his pad.

In the clip, you see Chrisean -- wearing the same pink track suit from earlier in the day -- getting Blueface to herself on one side of a car (presumably hers). We're told she was trying to get him inside to leave with her. Instead, she threw hands with 2 ladies on the scene.

Chrisean finds a way to her feet -- and in the end, eyewitnesses tell us she and Blue left in different vehicles. Unclear if they met up somewhere after, or went their separate ways.

Of course, this is disturbing on many levels. For one, it's another instance of violence between Blueface, Chrisean and/or people in their orbit. More sad, though, is the fact that Chrisean says she's got a bun in the oven -- so this is super dangerous in that regard.

Remember, Blueface has denied the kid is his ... and also said he and Chrisean were done. It seems she might've wanted to patch things up -- which doesn't seem to have ended well.