Joshua will take on Carlos Takam this weekend in pursuit of win No 20, the Frenchman having replaced injured Kubrat Pulev last week.
He will defend his WBA and IBF world heavyweight titles as well as his unbeaten record, having come of age as a boxer by getting off the canvas to beat Wladimir Klitschko earlier this year.
Joshua was also a successful amateur, winning gold at the GB Championships in Liverpool in 2010 before securing world super-heavyweight silver and Olympic gold in 2012.
However, he was far from untouchable and one man even managed to secure a knockout victory against the 6ft 6in Finchley fighter.
Mihai Nistor was already a national champion when he headed to the European Championships in Ankara back in June 2011.
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The Romanian recorded stoppages in both of his first two fights, beating Muhammet Guner of Tunisia in the first round of their bout and Bulgaria’s Petar Belberov in the second.
And while Joshua, his quarter-final opponent, got further than both of them, the Brit could not cope with his power.
Twice in the third round, Joshua was caught by the southpaw’s powerful left hand and given a standing eight-count with the referee deciding he could not continue after the second one.
Nistor was subsequently beaten by Italy’s Roberto Cammerelle in the semi-finals and despite his obvious talents and a famous win over AJ, has never turned professional.
But the 27-year-old still has fond memories of that win in Ankara.
“It was a special day,” he said.
“My trainer said: ‘Don’t worry, Joshua is big but he’ll go down quickly if you punch him correctly.’
“I didn’t know who he was or what he was going to become.
“He was a good boxer, he was moving all the time and he had a strong punch.”
He added: “I beat him in 2011 and in 2012 he was an Olympic champion!”
But Nistor himself was unfortunate not to qualify for London 2012 although he did fulfil his Olympic dream four years later as Romania’s only boxing representative in Rio.
However, he got a slice of bad luck again, losing a close decision to Jordan’s Hussein Ishaish.
He has remained an amateur, with funding from the army, but will hope by the end of his career in the ring, the win over Joshua six years ago is not the high watermark.