The 27 year-old won almost every round of the twelve on home soil to build on his impressive dethroning of Katsunari Takayama in December when Argumendo claimed the red strap in an upset victory.
Argumendo moves to 18-3-1 with the triumph and further towards a potential unification at the weight, whilst Mendoza drops to 11-5 after suffering a second defeat in his last three bouts.
Judges carded 119-109 and 118-110 (twice) for Argumendo who was in cruise control at times in the contest.
‘Tecuala’ has lost just once in the last four years, a close split decision reverse against Carlos Velarde – a result that could easily have gone either way.
Velarde, 25, went on to lose a world title challenges at both 105 and 108 pounds against Ryo Miyazaki and Donnie Nietes respectively in May 2013 and November 2014, but could be handed a third chance should Argumendo aim for a revenge mission in 2016.