Liam Paro defeated incumbent IBF super lightweight champion Subriel Matias on Saturday evening in Puerto Rico.
The Australian made the long journey to travel to the territory, with Matias enjoying vociferous home support.
However that was not enough for Matias, who suffered a comprehensive unanimous decision defeat with scores of 116-111, 115-112, 115-112.
Paro retained his unbeaten record and he won the majority of the rounds as his opponent struggled to find his best form in the ring.
Matias attempted to put the pressure on after the early rounds but the doughty challenger was not cowed by the pressure, and he grew in confidence as Matias struggled.
The referee warned Paro three times in the first four rounds for leading with his head, and Matias hinted at a breakthrough in round six when a heavy blow rattled his opponent. In the seventh, the referee finally docked Paro before he recovered to dominate into the championship rounds.
For Paro there could be the chance of a rematch with Matias, while he also may pursue a clash with Jack Catterall, who recently won his rematch with Josh Taylor.
Devin Haney, the WBC champion at super lightweight, could be on the hunt for a new triumph after losing to Ryan Garcia in controversial circumstances, while Isaac Cruz and Teofimo Lopez hold the WBA and WBO belts, respectively.
Live on DAZN : Check your region for PFL and PFL Europe on DAZN . Click here for details.