It was a big right hand which turned a fight, and a fighter’s fortune, around tonight.

At UFC Fight Night: Jacare vs. Mousasi in Connecticut, Ben Rothwell scored a first round knockout victory for the ages against the heavily favored Alistair Overeem.

After losing the bout’s opening exchanges to Overeem, Rothwell landed a sudden overhand which struck the Dutchman above the ear.

Overeem crumbled to the mat, where Rothwell followed up with right hands until a referee intervened.

Overeem had landed punches, kicks, and knees in his typical style. But, there’s just no margin of error in MMA — especially with huge heavyweights throwing heavy punches with 5 oz gloves.

“This is what happens when you believe in yourself,” Rothwell said after scoring the stunning upset. “It’s time to make my way to the title.”

Rothwell advances to 34-9 with the victory.

Overeem drops to 37-14-1 with the loss. He was rated #7 among UFC heavyweights going into the bout, and about a four-to-one favorite.

At UFC Fight Night: Jacare vs. Mousasi, Ben Rothwell defeated Alistair Overeem by TKO (punches) at 2:19 of round one.