Kell Brook did not make it past the sixth round in his bid to overthrow Gennady Golovkin as middleweight champion.
The undefeated Kazakh (36-0 33KO) was up to the task against a younger Brook, who jumped up two weight divisions to challenge GGG.
The 30-year-old British boxer was breaking Golovkin’s defence and landing a few punches. Buy the 34-year-old boxer shook him up the most with his heavy punches.
And with shots raining down on Brook in the fifth round, his trainer Dominic Ingle threw in the towel.
It was Brook’s first defeat in his 37th professional fight, while the undefeated GGG now has 33 knockouts from 36 fights, including 23 in a row.
GGG backed Ingle’s decision, saying: “I think he’s smart, I respect his corner. Seriously, the last round he couldn’t breathe or move.”