The Atlanta M.C. dropped the controversial bar in his "Turn Yo Clic Up" collab with Quavo on Friday ... rapping in his verse, "I got it out the field, f*** Russell."

Future hasn't shied away from his thoughts on his ex-fiancée and mother of his child, Ciara, moving on with the NFL quarterback ... going in on the now-married couple multiple times in interviews.

Remember, Future Hendrix bashed Ciara for having Russell around Future Jr. early in their relationship ... telling "The Breakfast Club" in 2015, "You don't bring a man around your son."

"You've known this man for a few months and you're bringing him around your kid? Who does that?"

He later went in on Russell in 2019 ... saying he's not a real man in their relationship.

"He not telling her, 'Chill out with that on the internet. Don't even talk to him. I'm your husband. You better not even bring Future's name up!" he said on Apple Music.

"If that was me, she couldn't even bring his name up. She know that. She couldn't even bring her exes names up."

Russell and Ciara have been married since 2016 ... and they have two kids of their own.

Wilson has since become a father figure for Future Jr. as well ... even spending a lot of time working on their football skills together.

Russell doesn't seem bothered by Future's constant gripes -- this past Father's Day, he said, "Future, Sienna & Win ... I Love You Forever! Glad we get to raise them together Momma! @ciara."