WATCH: Huge underdog finishes top flyweight to score sublime upset victory at UFC Portland

Brandon Moreno may very well have emerged as a legitimate 125 lb contender following his outstanding UFC debut.

All the odds were stacked against Moreno heading into UFC Portland. With Sergio Pettis pulling out of his scheduled bout against Louis Smolka a week and a half before fight night, the Mexican was rushed into the big leagues on extremely short notice. Smolka was ninth in the official rankings, had been riding a four-fight win-streak and was on the cusp of securing a title shot while Moreno was coming off a second round submission loss to Alexandre Pantoja in an exhibition on season 24 of the Ultimate Fighter. All these factors contributed to the Vegas bookies having Smolka as a -400 favourite, while Moreno was written off as a +325 underdog. He was by far the biggest underdog on the card. However, Moreno didn't let everyone else's expectations weigh him down and he was brimming with confidence. He nailed an early takedown and after a scramble, he saw his opening sunk in a guillotine choke that left Smolka floundering on the ground. Smolka tried his best to escape, but the choke was just too tight and he was forced to tap at 2:23 of the opening stanza, meaning Moreno walked away with the victory and a lucrative Performance of the Night bonus worth $50,000. The GAA Hour podcast is out every Monday and Thursday. Subscribe here on iTunes or listen on Soundcloud (if you want to).