Kazuto Ioka (right) lands a stiff jab to Roberto Sosa en route to a unanimous decision victory in Osaka, Japan on Sept. 27. Photo by Buddhika Weerasinghe / Getty Images

Kazuto Ioka cruised to his fourth straight win, defeating Roberto Sosa by one-sided unanimous decision on Sunday at the EDION Arena in Osaka, Japan. Ioka won by scores of 120-108 and 119-109 (twice).

Ioka, a former unified WBA/WBC strawweight titleholder and WBA junior flyweight titleholder, controlled the early rounds with his jab, forcing “Incho” Sosa to lunge from the outside. Ioka rocked Sosa late in round two with a left hook that sent him reeling to the ropes at the bell.

Ioka (18-1, 10 knockouts) never had to get out of first gear as he deftly evaded the shorter Argentinian’s blows and boxed his way to the center of the ring, where he picked his counterpunching opportunities at his leisure.

Sosa (26-3-1, 14 KOs) had previously beaten current IBF junior bantamweight titleholder Zolani Tete but was fighting outside of his native country for just the second time.

The bout was for the WBA regular flyweight title, which THE RING doesn’t recognize as a world championship. The legitimate WBA title is held by WBO/WBA unified titleholder Juan Francisco Estrada, who defended his title a day earlier with a tenth-round technical knockout of Hernan Marquez.

The 26-year-old Ioka, THE RING’s No. 4-rated flyweight, keeps pace with Juan Carlos Reveco, the Argentinian whom Ioka topped by a majority decision in April and is expected to face once more in the near future. Reveco, rated No. 5 by THE RING, stayed busy by beating unheralded trial horse Breilor Teran in Argentina the day before.