The unbeaten junior lightweight prospect overcame a sixth-round knockdown to outpoint Romania’s Costin Ion over eight rounds.
The referee scored the contest for Fiaz on points in their DAZN-aired main card bout Saturday evening from the AO Arena in Manchester.
Fiaz was well in control through five rounds.
The Jaime Moore-trained boxer was denied a knockdown call of his own when the referee correctly ruled that he cuffed the head of Ion and pushed him to the canvas along the ropes.
Ion stood in the pocket and braved every punch thrown in his direction.
It reaped major dividends as he floored Fiaz late in round six.
The two traded left hooks, Ion quicker to the draw as Fiaz fell to the canvas.
The 23-year-old local favourite beat the count, but spent the rest of the round attempting to find his legs and clear his head.
The same weapon continued to land for Ion in the seventh and eighth round, but not enough to the point of pulling off what would have been a leader for 2023 Upset of the Year.
Fiaz was able to box and bang his way to the final bell and courageously preserve his unbeaten record as he advanced to 12-0 in the paid ranks.
A few thousand people were in attendance and nearly 1,000 travelling fans from Oldham were there to cheer on Fiaz until the final bell.
Manchester United footballer Alejandro Garnacho was also in attendance, supporting his friend Fiaz, and even paid a backstage visit before the big fight.
At 23 years old, fiaz has now cemented his place in the top six in the country, closely behind Zelfa Barrett, after defeating a highly ranked contender in Costin Ion.
Promoter Eddie Hearn later confirmed his next fight will be for a title.
