Guadalupe Martinez had every reason to lose Saturday night.

She was facing Zulina Munoz, who had not lost in 34 bouts and is considered one of the top female fighters in the world. Martinez could have put on a decent performance and collect a nice purse, but Martinez believed she could grind out a win.

Martinez did just that, scoring a huge upset victory over Munoz to capture the WBC junior bantamweight title at the Arena Oasis in Cancun, Quintana Roo, Mexico.

With the win, Martinez goes to 15-9, with five knockouts. Munoz falls to 48-2-2, with 28 KOs.

Munoz was making her 11th defense of the WBC title Saturday night. On paper, it looked like she would get it as Martinez, despite winning more fights recently, had lost her half of her first 12 bouts as a pro.

Martinez utilized the same strategy throughout the fight, walking down Munoz throughout the fight. When she closed the gap or had Munoz against the ropes, Martinez let her hands go, scoring repeatedly with right hands to the head.

A accidental clash of heads opened a cut over Munoz’s eye. Per WBC rules, referee Gary Ritter deducted a point from Martinez at the start of the sixth round.

Sensing she was down on the scorecards, Munoz increased her punch output during the final two rounds, but was not able to score or land anything significant.

Scores were 96-93, 96-93, and 95-94 in favor of Martinez.

Also on the Zanfer Promotions card, welterweight Ivan Alvarez dropped Abner Lopez (25-7, with 21 KOs) in the second round en route to a unanimous decision over 10 rounds.

Scores were 98-91, 98-91, and 99-90 for Martinez, who improves to 26-7, with 17 KOs.

Fringe junior middleweight contender Roberto Garcia (40-3, with 24 KOs) won an eight round unanimous decision over Nestor Garcia (22-13-1, with 17 KOs).

Scores were 76-75, 76-75, and 77-74 in favor of Roberto Garcia, who has won his last 12 bouts since his defeat to Antonio Margarito in May of 2010.

Francisco A. Salazar has written for RingTV since October of 2013 and has covered boxing in Southern California and abroad since 2000. Francisco also covers boxing for the Ventura County (Calif.) Star newspaper, Boxingscene.com, and Knockout Nation. He can be reached by email at [email protected] or on Twitter at FSalazarBoxing