An unbeaten but unknown southpaw upset one of Gennadiy Golovkin’s prospects Friday night in Hollywood, Florida.

Carlos Gongora survived serious trouble in the second round and engaged in an action-packed dogfight with Ali Akhmedov until he knocked out Akhmedov in the 12th round of their fight for the then-vacant IBO super middleweight title. Ecuador’s Gongora (19-0, 14 KOs) dropped Kazakhstan’s Akhmedov twice in the 12th round, before referee Frank Gentile halted the action at 1:57 of that final round.

The 25-year-old Akhmedov (16-1, 12 KOs), a Kazakhstan native who is promoted by Golovkin’s company, was ahead on all three scorecards entering that final round. He suffered this stunning defeat on the undercard of Golovkin’s mandated IBF middleweight title defense against Kamil Szeremeta at Seminole Hard Rock Hotel & Casino.

The William Hill sports book listed Akhmedov as a 14-1 favorite entering their thoroughly entertaining encounter.

Gongora sent a battered, bloodied and fatigued Akhmedov to the canvas with a left uppercut 54 seconds into the final round. Akhmedov answered Gentile’s count, but clearly was still hurt.

Akhmedov attempted to hold and survive, but the crafty, intelligent Gongora knocked him down again, with another left uppercut. Akhmedov hit the canvas the second time with 1:13 to go in the bout, but Gentile stopped counting at seven and waved an end to the bout as Akhmedov struggled to get up.

“I was a little worn down for the 12th round, as you can tell,” Gongora told DAZN’s Todd Grisham through a translator. “But I knew I had to dig deep, and I knew he had to dig deep as well. And I just found it deep down inside, and I had to pull it out of me, and I had to trade with him and win that last round to get the win.”

With the outcome of their match seemingly in doubt, Akhmedov and Gongora spent the entire 11th round hammering away at each with power shots from close distances. Neither fighter appeared hurt in that round, but both boxers landed plenty of flush punches.

Gongora continued to fight Akhmedov inside in the 10th round and withstood Akhmedov’s power well.

A right-left-right combination by Gongora backed Akhmedov into the ropes with 1:10 to go in the ninth round. Akhmedov regained his composure and landed several right hands later in the ninth, but the composed Gongora took those shots well and continued connecting on the inside.

Gongora rocked Akhmedov with a left hand just after the midway mark of the eighth round. Akhmedov connected with two right hands in the final minute of the eighth round that slowed Gongora’s punch output.

Gongora landed a right to Akhmedov’s body and quickly followed up with a right hook to his head a little more than a minute into the seventh round. Later in the seventh, Gongora cracked Akhmedov with a left uppercut that moved him backward.

By then, Akhmedov had swelling and a cut around his right eye.

Akhmedov’s right hand snapped back Gongora’s head and moved him into the ropes 25 seconds into the sixth round. Though he appeared hurt, Gongora fired back with a straight left that landed.

They traded on the inside for much of the final minute of the sixth round.

Gongora’s straight left connected just before the halfway point of the fifth round.

Gongora landed a straight left with 1:20 to go in the fourth round that stopped Akhmedov from punching temporarily. Less than 10 seconds later, Akhmedov seemed to stagger Gongora with a jab.

After a tough second round for Gongora, he regained his legs in the third round. Akhmedov caught him with an overhand right with 30 seconds to go in that third round, but Gongora took it well.

Akhmedov rocked Gongora with a right-left combination 18 seconds into the second round, which made Gongora hold Akhmedov and move around. Akhmedov’s right hand to the top of Gongora’s head hurt him again 52 seconds into that second round, but the veteran managed to survive to the end of that round.

Gongora landed two straight left hands in the opening round, the first 50 seconds into it and another with about 40 seconds remaining in it. Akhmedov stalked Gongora for much of those opening three minutes, but Gongora boxed and moved well.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.