Gennady Golovkin vs. Kell Brook: Live Round-by-Round Results and Highlights

Gennady Golovkin retained his unified middleweight championship with a fifth-round stoppage of Kell Brook on Saturday night at the O2 Arena in London. 

It wasn't the prettiest performance of GGG's career, but he got the job done and extended his knockout streak to 23 fights. 

Golovkin (36-0, 33 KO) seemed hell bent on knocking Brook out early, and that made him sloppy at times. He came out attacking in the opening round and hurt the challenger with a hard left hook along the ropes that damaged his right eye.

Brook (36-1, 25 KO) stood in the pocket and gave as good, if not better, than he received in the second round and didn't seem to have very much trouble catching GGG coming inside over the next couple of rounds.

But the power shots from the larger fighter started to take their toll.

Golovkin came out aggressive in the fifth and began to open up his attack with ripping shots to both levels. Brook appeared in serious trouble and favoring his eye when his corner suddenly threw in the towel and stopped the fight.

Brook reportedly suffered a broken eye socket, prompting the stoppage.