If the two ever meet in the Octagon, and the action is as heated as their trash talk, we're in for an epic encounter.
Melendez, the long-time Strikeforce lightweight champion, and Alvarez, his two-time Bellator counterpart, were long considered among the top non-UFC lightweights, if not the two very best, for quite some time.
"I feel he's fallen off the past couple years, to be honest," Melendez recently told reporters. "Maybe our paths will cross now. And I'm so not scared at all if that's the case."
Apprised of Melendez's comments, Alvarez couldn't resist returning fire.
"Oh, is that what he thinks?" Alvarez told MMAFighting.com. "Tell you what, I think Diego Sanchez must have really landed good with those uppercuts when they fought last year, if that's the case. He must still be feeling them."
Melendez has made it clear he considers himself above Alvarez in the pecking order. He meets fellow TUF 20 coach Anthony Pettis for the latter's UFC lightweight title on Dec. 6 in Las Vegas.
In Alvarez's ideal scenario, he'll beat Cerrone, Melendez will knock off Pettis, and the winners will tangle.
"I hope Melendez beats Pettis," Alvarez said. "Nothing against Pettis, but I want Melendez to win that fight. I want to beat Donald and then finally get my hands on Melendez with the title up for grabs. Best of all worlds."