It gained its name from the moment at the end of the eighth round when Durán turned away from Leonard towards the referee and quit by apparently saying, "No más" (Spanish for "No more").

Leonard was defending the World Boxing Council (WBC) Welterweight Championship for the second time.

Leonard abandoned his usual slick boxing style and stood flat-footed with Durán.

Late in the round, winding up his right hand as if to throw a bolo punch, Leonard snapped out a left jab and caught Durán flush in the face.

In the closing seconds of the eighth round, Durán turned his back to Leonard and quit, waving his glove and apparently saying to referee Octavio Meyran, "No más" ("No more" in Spanish).

Leonard was the winner by a technical knockout (TKO) at 2:44 of round 8, regaining the WBC Welterweight Championship.

Within hours, commercials featuring Durán (in both Panama and the United States) were ordered off the air.

[8] On June 16, 1983, Durán's 32nd birthday, he knocked out undefeated Davey Moore in the eighth round to win the WBA Junior Middleweight Championship.