ESPN commentator Dan Hardy called it "the most spectacular knockout we have ever seen" while renowned MMA reporter Ariel Helwani was spruiking the KO as the best of the century.
Combat sports analyst and podcaster Luke Thomas tweeted: "That's one of the best KOs in UFC history."
Sports writer Sam Vecenie said: "That Joaquin Buckley knockout is one of the best I've ever seen in the UFC. Oh my god.
"I honestly didn't know people could do this outside of movie fight choreography. What in the world."
MMA writer Jose Youngs added: "OH. MY. GOD. Joaquin Buckley just scored one of the most spectacular headkick knockouts I have ever seen."
ESPN's Marc Raimondi wrote: "I don't think I've ever seen that before in MMA. Take a bow, Joaquin Buckley. KO of the Year candidate."
The UFC's official Twitter account called it "the most unbelievable KO in UFC history" while president Dana White asked his 5.4 million followers: "Is this the greatest KO in UFC history?"
Heavyweight Daniel Cormier also chimed in. "I mean I've seen some s**t in MMA, but that may be the craziest knockout ever!!!! Dude got some bonus money coming his way!!!!" he wrote.
The violence kept coming as Chris Daukaus nailed Rodrigo Nascimento with a left hook then followed up with a flurry of punches and elbows to the head that forced the referee to call their fight off after just 45 seconds.
Next up was Tom Breese, who knocked KB Bhullar down early in Round 1 with a jab, then finished the fight off on the ground.
