Joshua, the British star, knocked down Ngannou in the first round, knocked him down again in the second round and then delivered the knockout punch at 2:38 of the second round.

The knockout blow, a powerful right hand, left Ngannou out cold. Ngannou, the former UFC champion, was down on the canvas for more than a minute and received oxygen, according to the DAZN broadcast.

The victory was the fourth straight for Joshua (28-3) after his back-to-back losses to Oleksandr Usyk of Ukraine.

“For me, I don’t know if I’m coming into my peak,’’ he said. “I’m just pushing day by day.’’

It was a stunning setback for Ngannou, who knocked down Tyson Fury during his pro debut in October and looked impressive in a split-decision loss. But Joshua, the two-time world champion, was in control from the outset Friday.

Joshua, 34, said he was captivated by Ngannou’s bout with Fury.

Recalled Joshua, “When I saw the fight with him and Fury, I was like, ‘Damn, this guy can fight.’ So I said, ‘I need a piece of that.’ “

But after the fight started Friday, Ngannou, the 37-year-old native of Cameroon, spent almost as much time on the canvas as he did on his feet.

“He’s a great champion,’’ Joshua said of Ngannou (0-2) after scoring the 25th knockout of his career. “And this doesn’t take away anything from his capabilities. …He can come back.’’

-USAToday