How did Alistair Overeem split his lip?

Alistair Cees Overeem was born in Hounslow, England, but lived in Holland for the majority of his life.

After his mother and their father divorced, Alistair was sent to Holland at the age of six along with his older brother Valentijn Overeem. At the age of 15, Valentijn brought Alistair to a gym to study self-defense, which sparked his interest in combat sports.
In a kickboxing match that followed K-1 regulations in 1997, Overeem made his debut in combat sports competition. He defeated Paul Hordijk by decision in his debut match of professional kickboxing in March 1999. He also participated in a Mixed Martial Arts (MMA) match against Ricardo Fyeet in that year, which he won via first-round submission. With Japan’s Rings organization, he engaged in his second MMA match.

How did Alistair Overeem split his lip?

A fight between Alistair Overeem and Jairzinho Rozenstruik at UFC on ESPN 7 resulted in one of the most horrifying-looking injuries in the promotion’s history.

With just four seconds remaining in the heavyweight fight, Rozenstruik submitted Overeem to finish it. Overeem’s lip was severed in half by a right-hand punch from Rozenstruik that also knocked him to the ground.