Rhys McKee made an eye-catching move up to welterweight at Cage Warriors 110 in Cork after knocking out Håkon Foss after just 63 seconds.
The Ballymena fighter floored his opponent with a solid jab and finished the contest with a flurry of strikes on the grounded Norwegian.
Earlier, Belfast's Joe McColgan also impressed with an early submission over England's Robbie Scott.
Decky McAleenan secured a unanimous victory over Antanas Jazbutis.
In his first bout since stepping up from lightweight, McKee extended his record to 10-2-1 with all 10 victories coming by stoppage.
McKee was previously offered a title fight at lightweight but decided to move up a weight division to benefit his longer term health and career, and he immediately sent out a statement to the rest of the division.
After his victory, the 24-year-old looks destined for a Cage Warriors title shot and a possible UFC contract after a commanding victory.
"I'm not here to mess about, I'm here to finish" McKee told Cage Warriors on UFC Fight Pass, before admitting it was the most nervous he had ever been for a fight.
"I'm here to stay," added McKee before calling on Cage Warriors to give him a title shot in Belfast in next year.
McColgan dispatches Scott
In the co-main event, Joe McColgan wasted little time in defeating Robbie Scott after he submitted the Englishman with a D'arce choke after one minute and 27 seconds.
Kuwait-based Scott took the fight against the the Belfast man on a week's notice and McColgan told BBC Sport he couldn't see the contest going beyond the second round.
McColgan set the tone in the opening seconds with a hard body kick before the fight went to the ground, and after an intricate grappling exchange the 33-year-old secured the D'arce to take his record to 6-2-1.
"He gave up the underhook and once you give that up it's just a matter of me linking up my hands, and then the D'arce is on," said McColgan.
"It's one of my favourite moves. I get it on everyone."
McAleenan comfortable against Jazbutis
Earlier in the evening, Decky McAleenan got back to winning ways after securing a unanimous decision victory over Antanas Jazbutis, with all three judges scoring the contest 30-26.
It was a much needed win for the Newry man after losing his last two Cage Warriors fights to Steve Aimable and Tom Mearns in tight contests.
The 28-year-old dominated the fight after a patient start and Jazbutis survived a dominant third round from McAleenan, who tried to end the fight with several submission attempts after taking his back.
In the other main card bouts, Belfast's Ciaran Mulholland lost his professional debut after being submitted with a rear naked choke in the second round by England's Nathan Fletcher.
Cork's John Mitchell won a unanimous decision against Dublin's Eric Nolan, while rising star Ian Garry submitted Mateusz Figlak with a first round rear naked choke.