Anthony Joshua's IBF, WBA and WBO title defeat by Andy Ruiz Jr represents one of the biggest shocks in heavyweight boxing.
Here, Press Association Sport revisits five others.
Mike Tyson v James 'Buster' Douglas, February 1990
Tyson was perhaps the world's most famous individual, and was regularly being described as the finest heavyweight of all time, when he travelled to Tokyo for what was supposed to be a routine defence of his IBF, WBA and WBC titles. Douglas was a 42/1 underdog, and forced not only an exceptional fight, but what is still considered the greatest upset of all time when, shortly after the death of his mother, he refused to be bullied by Tyson, resisted his aggression and capitalised on his poor preparation to stop him in the 10th. He had also recovered from an eighth-round knockdown.
Wladimir Klitschko v Tyson Fury, November 2015
The great Klitschko had reigned as champion for nine years, and against the enigmatic Fury was expected to make his latest routine title defence, but Fury travelled to Germany and out-fought and out-thought him to shock him and earn scores of 115-112, 115-112 and 116-111 from the three judges. Klitschko had not lost since 2004, and had made 19 successful title defences.
Lennox Lewis v Hasim Rahman, April 2001
Lewis was the world's leading heavyweight and in his prime, again making him a significant favourite against his American challenger, and to the extent that a fight with Mike Tyson was already being planned. Yet at altitude in Johannesburg, South Africa, Rahman found a life-changing punch to stop Lewis in the fifth, inflicting the then-defending champion's second ever defeat.
Muhammad Ali v George Foreman, October 1974
For all of Ali's popularity, there were concerns for his life against the then-undefeated Foreman, who before their fight in Zaire had devastated the great Joe Frazier and established himself as perhaps the most powerful puncher in history. Even those in Ali's camp felt defeat likely, but he not only absorbed punishment from Foreman, he produced one of his smartest and bravest performances to stop him in the eighth as he tired, winning the Rumble in the Jungle and securing his most famous win.
Lennox Lewis v Oliver McCall, September 1994
Lewis was making the fourth defence of his WBC title, and was respected enough that Riddick Bowe had recently refused to fight him, when the seemingly-unremarkable McCall travelled to London as his latest challenger.
When Lewis threw a right in the second round, McCall responded with a left and right that landed flush on his chin, and stopped him after only 31 seconds of the second round at Wembley Arena.