During Monday's bout, Uchiyama was in control as he deflected the nervous jabs of Vasquez, who was visibly running out of steam as the fight progressed, reports Xinhua.
In the eighth round, Uchiyama delivered a heavy blow to Vasquez's face, then followed up with a series of punches that forced the referee to suspend the fight and declare a technical knock out (TKO) by the Japanese featherweight.
Vasquez's defeat dashed any hopes Costa Rican boxing had of winning a world title before the close of 2012, or of winning a men's world boxing championship for the first time ever.
To date, the only Costa Rican ever to win a world boxing crown is Hanna Gabriel, Vasquez's wife, who currently holds the World Boxing Organisation (WBO) super welterweight title.
