The heavyweight main event looked to be slipping away almost as soon as it began.

Prenga stunned Joshua in the opening round with a right hand before driving home an uppercut that sent the former unified heavyweight champion crashing to the canvas. Joshua beat the count, but moments later his glove touched the canvas again after another heavy attack, resulting in a second knockdown.

Joshua survived the remainder of the round under intense pressure as Prenga sensed the biggest victory of his career.

The fight turned completely in the second.

Joshua settled behind his jab and began timing Prenga’s forward attacks with sharper right hands. Prenga still found success on the inside with another uppercut, but Joshua answered immediately, driving home a huge right hand that changed the fight.

Seconds later he unloaded another crushing right that sent Prenga tumbling through the ropes, leaving the referee with no choice but to wave the contest off.

Heavyweights can change a fight with one punch.

Joshua looked on the brink of defeat after the opening three minutes, yet recovered his composure, rebuilt behind the jab and produced the type of finishing sequence that has defined the biggest wins of his career.

The victory keeps Joshua on course for the proposed November showdown with Tyson Fury, who stopped Mariusz Wach in Thailand less than 24 hours earlier.

After a disastrous opening round, Joshua answered every question in emphatic fashion.