Klitschko took charge from the fifth and Brock had no answer

Klitschko was initially content to pick up points with his jab but stepped it up after an accidental clash of heads cut him over his left eye in the sixth.

The Ukrainian then launched a big right and, though the challenger got up on eight, referee Wayne Kelly halted it.

It took Klitschko's record to 47-3, while Brock lost his first fight in 30.

"I knew it was over there," the champion said after his combination did the job.

"I should have tried that earlier, but it took me time to get my distance and rhythm. He was a good defensive fighter."

Brock added: "I saw the punch coming, but I couldn't react fast enough.

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"He had a better jab than I thought he did. He was very strong."

It did not go all Klitschko's way early on, as Brock landed some body shots and managed to evade the Ukrainian's jabs.

But it was only a matter of time before the 30-year-old champion took charge and showed why he is regarded as the best of the four heavyweight champions.

He thrilled a 14,260 crowd at Madison Square Garden which included Muhammed Ali by punishing the American with his stinging left in the fifth.

And he did not have long to worry about what effect the cut would have, landing a succession of big blows before sending the challenger sprawling.