New York ? Wladimir Klitschko stunned Calvin Brock with a sharp left, then finished him off with a thunderous right late in the seventh round Saturday night to successfully defend his IBF heavyweight title in a surprisingly competitive fight.

Klitschko rarely threw the right as he piled up points with his jab. But he found the range with the right midway in the bout, and Brock had no chance when Klitschko opened up the challenger’s defense with another quick left. The big right immediately followed, and Brock fell face-down to the canvas.

He got up at eight, but was wobbly, and referee Wayne Kelly stopped it at 2:10.

“I knew it was over there,” Klitschko said. “I should have tried that earlier, but it took me time to get my distance and rhythm. He was a good defensive fighter.”

Klitschko, in his first defense of the crown he won from Chris Byrd in April, was cut over the left eye in the sixth round by an inadvertent head butt. Perhaps wary of the cut getting worse, he unloaded several massive punches late in the sixth and through the seventh rounds.

“It was easy to hit him with the right hand there,” Klitschko said of the knockout punch.

Did he feel any urgency because of the cut?

“Yes,” the champion said. “But I was leading at that time.”

The native of Kazakhstan, who represents Ukraine, improved to 47-3 with his 42nd knockout. Brock, a 2000 U.S. Olympian, lost for the first time in 30 bouts.

“I saw the punch coming, but I couldn’t react fast enough,” Brock said. “He had a better jab than I thought he did. He was very strong.”

Klitschko’s brother, Vitali, now retired, once held the WBC crown and was considered the better of the two fighters. But Wladimir showed Saturday why he generally is looked upon as the best of the four heavyweight champions.

He certainly thrilled the Madison Square Garden crowd of 14,260 that often chanted his name by leveling Brock with the classic left-right combination.

Until then, Klitschko was ahead on all three judges’ cards, but he was getting a stiff challenge from Brock – even though Brock came into the fight with unimpressive credentials despite never having lost as a professional.

Although he looked nervous and was awkward in the first two rounds, Brock began landing some body shots and avoiding Klitschko’s jabs for a while. But it was temporary, and the 30-year-old Klitschko took charge again in the fifth round.