This Saturday, was the first title defense of his WBC featherweight belt for Abner Mares. Needless to say he was probably hoping the outcome would have been a better one.

His opponent, Jhonny Gonzalez was the former title holder before losing it to Ponce De Leon, who Mares recently beat to claim the belt.

Mares was the favorite of the fight, having won titles in three weight divisions (Bantamweight, Super Bantamweight and Featherweight) and appearing unstoppable in recent outings.

Here is an interesting fact, at the age of 20 years old Mares was a sparring partner for Gonzalez. In fact, Gonzalez's trainer Nacho Beristain use to be the trainer of Mares, so the two fighters were definitely familiar with each other.

However, Saturday was all about Gonzalez catching Mares off guard and sending him to the canvas two times, winning the fight and shocking fans.

(Photo by Harry How/Getty Images)

Many are saying this is the biggest upset of the year for boxing, I might have to agree. At least for now, remember we still have Mayweather-Canelo, one of those undefeated fighters may lose their perfect records next month. Although the outcome of that fight won't be considered an upset, which ever way it goes there will be plenty who are "upset."

Here is the complete fight that took place this Saturday, don't worry its short but for all you that enjoy knockouts fast forward to 6:48 on the video.