Anthony Joshua will be under pressure to make a statement when he takes on Andy Ruiz Jr on his US debut at New York's Madison Square Garden on Saturday.
Here, Press Association Sport revisits five of the IBF, WBA and WBO heavyweight champion's finest fights.
Joshua v Dillian Whyte, December 2015
Joshua finally avenged the amateur defeat he had once suffered to his long-term rival, but only after having almost been stopped himself. A largely one-sided fight had featured Whyte demonstrating remarkable punch resistance amid seriously hurting Joshua in the second. Joshua gradually recovered and showed just how powerful he is by finding the explosive punch that had been needed to finally stop Whyte fighting on.
Joshua v Charles Martin, April 2016
Joshua's reign as champion began the night America's Martin travelled to the UK to make the first defence of his IBF title. His past victory over Whyte had suggested Joshua was not yet ready for world level, but even if Martin was an unremarkable heavyweight, the challenger was clinical in stopping him in only the second round and setting up the success that has since followed.
Joshua v Wladimir Klitschko, April 2017
Joshua's dramatic defeat of the now-retired Klitschko, who remains the finest heavyweight of the modern era, was widely considered the best world heavyweight title fight of the 21st century. He remained largely unproven at the very highest level, and at one point his relative inexperience appeared likely to tell. Joshua knocked Klitschko down in the fifth round and then almost punched himself out in pursuit of the stoppage that did not follow. Klitschko then capitalised by dropping Joshua even more heavily in the sixth, and continued to win the following rounds until the Brit responded again, producing a life-changing uppercut that knocked Klitschko down again and left him sufficiently hurt that Joshua was able to stop him in the 11th.
Joshua v Carlos Takam, October 2017
Having established himself as the world's leading heavyweight by retiring the great Klitschko, Joshua was expected to win his next fight with greater ease. That Takam was a late replacement, following the withdrawal of Kubrat Pulev, far from helped, but the challenger's impressive punch resistance taught Joshua a valuable lesson. Though their fight was largely one-sided, Takam's rough tactics unsettled Joshua, who learned that "headhunting" does not guarantee knockout victories. Takam was eventually rescued from taking further punishment in the 10th round, even if many observers felt the stoppage was premature.
Joshua v Alexander Povetkin, September 2018
The champion's past title defence involved him coming under greater pressure than on any other occasion, excluding his memorable victory over Klitschko. The aggressive Povetkin buckled his knees in the opening round and continued to force Joshua to fight at an uncomfortable pace until his ambition proved his downfall. The explosive right hand Joshua threw to transform the fight in the seventh round hurt Povetkin to such an extent he should not have been allowed to carry on. Joshua has perhaps never thrown a more impressive punch, and the stoppage that followed was a near-formality.
