Fajardo (14-3-2, 12 KOs) sent Reyes (18-2-1, 16 KOs) crashing to the canvas with the first punch he threw.

A curling left hook the home favorite didn't see coming was enough to wave the contest, as the 28-year-old looked unsteady on his feet and unconvincing after beating referee Mario Gonzalez's count.

However, he was given the benefit of the doubt. The onslaught continued sharply, Reyes down on one knee after absorbing a left hook and right hand before again rising to his feet at the count of eight. Fajardo charged at him once they resumed, pressed him towards the ropes and earned another knockdown with Reyes defenseless.

Reyes desperately sought more time to recover, deliberately spitting out his mouthpiece and forcing a temporary pause hoping he'd gather his bearings. It was too late.

Fajardo raced over after the added time, unloaded flurries to head and body before sending the Argentine crashing down once more with another left hook. This time, the official waved it off immediately to confirm a stunning upset leaving fans inside at the Club Atletico Santa Paula in disbelief as the Filipino wheeled away to celebrate.

Fajardo, who arrived in Argentina three days pre-fight after a whopping 38-hour trip from Manila, delivered a career-best win on enemy territory and can now look forward to a world title shot.

Reigning titleholder Masamichi Yabuki (19-4, 18 KOs) makes his second defense against Mexico's Rene Calixto (24-1-1, 10 KOs) as part of a June 6 doubleheader in Japan and while in-form, the 33-year-old isn't unbeatable.

Filipino media have since reported October as a realistic timeline for Fajardo's world title shot, assuming the Yabuki-Calixto winner emerges injury-free.