Yeah, these guys HATE each other.

Here's the deal ... right after the Rams defeated the Giants on Sunday, Jalen Ramsey and Golden Tate got into a straight-up fist fight at midfield.

Ramsey and Tate really don't like each other -- Jalen used to date Golden's sister, and has two kids with her.

But, the couple went through a public breakup last year ... and after the split, Golden accused Jalen of not treating his sister well.

"I’m not happy at all with the disrespect that he’s shown towards my sister," Tate told The New York Post last year, "and the things he’s done in the past, but I don’t really want to go too much into it."

In fact, when a fan on social media insisted Golden was going to have to talk with Jalen over the end of the couple's relationship ... Tate said, "He know he gonna have to see me."

Fast-forward to Sunday afternoon at SoFi Stadium in Los Angeles ... and Jalen saw Golden alright.

After the Rams finished beating the Giants, 17-9, Tate and Ramsey reportedly threw haymakers at each other in a wild fight near the 50-yard line.

That, of course, ignited an all-out brawl ... with players leaving both bench areas to enter the fracas.

Fortunately for both teams, nobody appeared to be injured in the melee -- and it was all broken up after just a few minutes.

But, after the game, Ramsey reportedly wanted round 2 with the Giants star ... ESPN reported the defensive back lingered outside the Giants' locker room after the fight to try to get another piece.

The two, however, did NOT ultimately meet up again for a 2nd go-around.

Neither Rams coach Sean McVay nor Giants coach Joe Judge had too much to say about the incident after the game.

"I don’t know all the details," Judge told reporters, "so I’m going to reserve comment on that until I find out everything."