‘Finish of the year’: Bellator champ Pettis starches rival with sensational backfist KO (VIDEO)

Sergio Pettis sent MMA fans into meltdown after delivering a stunning spinning backfist finish at Bellator 272 which many considered a KO-of-the-year contender.

In his fourth fight in the promotion since leaving the UFC, Pettis defended the bantamweight title for the first time since winning the strap via a unanimous decision over Juan Archuleta in May.

This time, in the headline bout in Uncasville, the brother of ex-UFC lightweight champion Anthony was far more decisive despite losing "just about every second of the fight" as ESPN described it.

Feeling the pressure in the fourth round of his clash with Kyoji Horiguchi, Pettis turned the tables instantly with a stunning spinning backfist KO that left the Rizin bantamweight ruler, considered one of the world's best fighters outside the UFC, out cold on the canvas.

Replying to a Bellator post that said the strike came "outta nowhere", the legendary BJ Penn replied "Congrats, champ" along with a pair of clapping hands. 

"Perhaps this may be 2021’s MMA KO of The Year!!!" suggested one happy fan.

"What the Hell. First time I felt Bellator is better than the UFC," said another. 

Pundit Ariel Helwani agreed and called it "without a doubt one of the best finishes of the year".

"And when you consider the stakes and how the fight was going it’s even more amazing," the Canadian added.

Similarly, Chamatkar Sandhu dubbed it "One of the OMG moments of the year!"

Incredibly, some observers claimed Pettis had got "lucky" with the strike – but were soon shouted down.  

"I came out here and got beat up for four rounds pretty much," Pettis admitted in a postfight interview.

"I was just like, 'Man, I'm losing this fight. I've gotta do something spectacular.'

"It came out at the right time," he concluded, on what was just his fourth career KO/TKO.

Just as well-received, however, was Pettis' refusal to follow through with a coffin nail strike when noticing that a grounded Horiguchi had already had his lights blown out. 

"This result is difficult to accept...," began a Japanese fan.

"But Pettis is a gentleman. Respect him."

As announced by his employers in the aftermath of their 2021 closer, Pettis will now enter an eight-man bantamweight Grand Prix next year.

With $1 million prize money up for grabs, Horiguchi might also get the chance to exact revenge on him.