by David P. Greisman

The Nevada Athletic Commission drug testing has come back with the four main fighters from last week’s pay-per-view card in Las Vegas — Floyd Mayweather, Robert Guerrero, Abner Mares and Daniel Ponce De Leon — testing negative for prohibited substances, according to Keith Kizer, the commission’s executive director.

Mayweather outpointed Guerrero in the main event on May 4, winning 117-111 on all three judges’ scorecards and improving his unblemished record to 44-0 with 26 knockouts. Guerrero fell to 31-2-1 with 18 knockouts and 2 no contests.

On the undercard, Mares knocked down Ponce De Leon twice en route to scoring an impressive technical knockout win, albeit one marred by what appeared to be an early referee stoppage in the ninth round. Mares is now 26-0-1 with 14 knockouts, while Ponce De Leon is now 44-5 with 35 knockouts.

Kizer said he is awaiting the drug test results for the other 12 boxers who appeared underneath Mayweather-Guerrero on May 4, as well as for the 14 fighters from the May 3 show that also took place in Vegas.

David P. Greisman is a member of the Boxing Writers Association of America. Follow David on Twitter @fightingwords2 or send questions/comments via email at fightingwords1@gmail.com