Golovkin did what no one else has managed to get anywhere near doing to Macklin. After some early jabs kept the Kazakh away early in the first, Golovkin piled on pressure by cutting off the ring with precise, almost robotic movement to launch vicious right hands that stunned Macklin when they landed. He was shaken badly and tangled in the ropes by the end of the round.
The dominance continued throughout the second, and Macklin could only retreat as Golovkin walked through his jab. A glimmer of hope came when Macklin got through with a right hand near the end of the round, which drew cheers from the crowd. But his face was already quite badly marked up from Golovkin's frighteningly accurate power shots.
Macklin decided throw caution to the wind and came out for a gallant tear up in the third, which worked briefly before Golovkin walked him to the ropes and popped in a left hook to the body which sent Macklin crashing down to the canvas where he remained for over a minute.
Macklin said after the fight: "Without a shadow of a doubt he's definitely the best I've fought.
"I had a plan to exploit his weakness, but he didn't let me get into any kind of rhythm at all.
"The shot he took me out with is one of my favourites. I've done many people with that one over the years, so i guess I was due one. I was so preoccupied with defending the uppercuts that he got me downstairs."
Any questions over Golovkin's ability to mix it with a fully-fledged middleweight will be quickly withdrawn. Macklin was his toughest, most experienced opponent to date, and the US based Kazakh walked through him with ease.
It's doubtful if there's anyone at middleweight that would seriously trouble him. Don't be surprised to hear Golovkin mentioned in the same sentence as Carl Froch shortly.
In Bolton, Anthony Crolla beat Gavin Rees by a majority decision to put himself in line for a world title shot.
Crolla edged an enthralling bout to win the vacant IBO inter-continental lightweight, with two judges marking it 116-113 and 115-113 in his favour and the third scoring the bout as a 115-115 draw.
Rees started well and won the opening two rounds, but Crolla upped the intensity as the fight went on and is now expected to fight world champion Ricky Burns.