Watch Now: UFC 249 Highlights: Francis Ngannou vs Jairzinho Rozenstruik (0:50)

The fight between Francis Ngannou and Jairzinho Rozenstruik on Saturday night was all but guaranteed to finish in a knockout as two of the hardest punchers in the UFC clashed. But Ngannou took any tension out of the fight when he unloaded a terrifying blitz of punches to win that UFC 249 heavyweight clash from VyStar Veterans Memorial Arena in Jacksonville, Florida.

Rozenstruik (10-1) threw a few early leg kicks, but Ngannou (15-3) flipped a switch and unleashed a flurry of massive shots that finished the fight just 20 seconds after the bout started. Ngannou missed with a right and left before another massive left hook landed flush to Rozenstruik's jaw. Rozenstruik crashed into the cage and slid down the fence as Ngannou continued to land punch after punch until the referee forced him to stop the assault.

"I mean, when I heard he called me out, I knew he didn't know what he was doing," Ngannou said after his victory. "He has a lot of potential, I just think he needs to take a step back. He wasn't ready for a fight against someone like me."

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Ngannou expressed his frustration with not fighting for the heavyweight championship as the division has been held in limbo awaiting a third fight between champion Stipe Miocic and former champion Daniel Cormier. Ngannou said he doesn't know where he fits in the division, but UFC president Dana White revealed earlier this week that the winner of this fight would be in line to fight the winner of the bout between Miocic and Cormier -- whenever that trilogy fight takes place.

"I don't know what it takes to have a title shot in the UFC. To be honest, I've made my peace with that. It's not that I don't care, but I don't want to feel like something is controlling me," Ngannout said after the fight. "With or without a title shot, I'm still a fighter and still have what I have and can make a statement. I had fun out there, it wasn't something I was chasing. When I chase the knockout, it doesn't work, so I don't chase anymore. When he called me out, I'm like, 'this guy doesn't know what he's doing.' He just came here and had a few knockouts, but I didn't see anything impressive, but I don't mind people calling me out."

Ngannou has now won four consecutive fights by first-round knockout.

For complete results, highlights and analysis of the action on Saturday night, be sure to visit the CBS Sports UFC 249 live blog