A fired-up WG says he broke from his boxing workout on Friday just to give Suge a piece of his mind ... responding to Suge making him his whippin' boy on the most recent 'Collect Call' podcast episode.

Suge claimed Snoop Dogg and Kurupt were Warren's ghostwriters on his 1994 debut album "Regulate... G Funk Era," which was released on a subsidiary label of Russell's Def Jam Records.

The album was a big hit ... it went 3X Platinum thanks to hits like "This D.J." and the certified hip hop classic "Regulate" with the late Nate Dogg -- a song Suge says he gave to Russell in good faith, having blown up on his "Above the Rim" soundtrack a year prior.

Now, because Snoop and Kurupt were signed to Suge's publishing, Suge expected a big payout, but says Russ pulled a fast one and falsely listed WG as a writer.

Suge also says Dr. Dre, who's Warren's stepbrother, used to beat Warren's ass for using phones in his presence ... for whatever reason.

According to Warren, Kurupt only assisted on the song "Do You See," and Snoop on "This D.J." ... but that's all.

Warren also denied the Dr. Dre beatdowns, but claimed he saved Suge from a couple of close calls at nightclubs back in the day -- he says he earned his ranking, and never had any ill will toward Suge.