If Jake Paul beats Anthony Joshua on Friday night, it will be a seismic shock of an unprecedented scale in heavyweight boxing history.
That is how big the gulf in class is between the YouTuber-turned-boxer (21-1, 7 KOs), who is outside the top 15 in all four world governing bodies at heavyweight, and two-time world heavyweight boxing champion Joshua (28-4, 25 KOs). By the time Paul had his first professional fight in 2020 (with no amateur career), Joshua had won eight world title fights and lost one, after winning an Olympic gold medal in 2012.
Victory for Paul would not only be so much bigger than the No. 1 upset this year in boxing (Rolando "Rolly" Romero's points win over Ryan Garcia in May), it would also eclipse some of the most famous surprise boxing results going back decades, such as points wins for Fritzie Zivic vs. Henry Armstrong (welterweight) in 1940, Randolph Turpin vs. Sugar Ray Robinson (middleweight) in 1951, and Sugar Ray Leonard vs Marvin Hagler (middleweight) in 1987.
Those fights featuring boxing legends were for world titles, a level Paul is still far adrift from at cruiserweight.
As well as experience and capability, there is also size: Paul is stepping up to heavyweight to face AJ. Oleksandr Usyk, the current world heavyweight No 1, successfully stepped up from cruiserweight to twice beat Joshua... but he is a former undisputed world cruiserweight champion and Olympic gold medallist.
Yet Paul's supporters point to the fact that Joshua has already been a victim of one of the biggest upsets in recent heavyweight history. In June 2019, nothing suggested a flabby Andy Ruiz would beat Joshua in New York, but the American recovered from a third-round knockdown to floor Joshua four times in a thrilling seventh-round TKO victory. However, Ruiz was no unknown challenger for Joshua's three world titles that night -- three years earlier, he lost a drab fight on points to Joseph Parker for the WBO world title.
Joshua avenged his defeat to Ruiz with a cautious points win six months later to regain the WBA, IBF and WBO belts. But an estimated 22 million have watched that humbling moment in the seventh round when Ruiz stopped him.
Losing to Paul would be even more humbling for Joshua. It would leave an indelible mark on his career, and irreparable reputational damage.
To put it in perspective just how much of a shock Paul beating AJ would be, it would be greater than these 10 iconic upsets in heavyweight boxing history.
11.2.1990: Mike Tyson L KO 10 vs. James 'Buster' Douglas, Tokyo
Douglas, a 42-1 long shot, took advantage of Tyson's poor preparation to floor the champion for the first time in his career in Round 10. Douglas, inspired by the recent death of his mother, used his superior reach to unload powerful jabs throughout the fight. Douglas recovered from a knockdown in the eighth round to deliver a stunning combination in Round 10, and become undisputed champion. It was a first professional loss for Tyson, who was known as the 'Baddest Man on the Planet' after terrorising the heavyweight division.
25.5.1964: Sonny Liston L RTD 6 v Cassius Clay, Miami
Clay, who later changed his name to Muhammad Ali, shocked the world when he forced feared champion Liston, a 7-1 on favourite, to retire on his stool at the end of the sixth round. Ali gracefully moved away from Liston's attacks early on, then landed pinpoint punches to leave Liston floundering in the sixth, to become the undisputed champion.
22.4.2001: Lennox Lewis L KO 5 vs. Hasim Rahman, South Africa
Lewis underestimated the altitude in South Africa and his American opponent by filming a part in Ocean's Eleven before the fight. Lewis was caught flush by little-known Rahman after dropping his hands in Round 5 for the WBC and IBF belts. Lewis also lost to Oliver McCall in two rounds in 1994, another big upset.
13.6.1935: Max Baer L PTS 15 vs James Braddock, New York
"The Cinderella Man" went from being a losing journeyman and on welfare in 1933 to world heavyweight champion when he outboxed big-hitting Baer, after starting a 10-1 underdog, in the world title fight.
30.10.1974: George Foreman L KO 8 v Muhammad Ali, Zaire
Ali employed "rope-a-dope" tactics to defeat world champion Foreman to regain the world heavyweight title at the age of 32 in the 'Rumble in the Jungle'. Ali came off the ropes in the eighth to floor a tiring Foreman, who was expected to overpower his fellow American.
19.6.1936: Joe Louis L KO 12 vs. Max Schmeling, New York
Louis was in formidable form and tipped to become champion when his unbeaten run hit the buffers. The German had ruled as champion (1930-31) but such was Louis' KO form, Schmeling started as a 10-1 outsider. Schmeling kept landing overhand rights to floor Louis three times in Rounds 4 and 12.
15.2.1978: Muhammad Ali L PTS 15 vs. Leon Spinks, Las Vegas
Spinks, the 1976 Olympic gold medallist, beat Ali on a split points decision in only his eighth professional fight. Ali, 36, was making an 11th defence but could not cope with 24-year-old Spinks' workrate.
9.11.1996: Mike Tyson L TKO 11 Evander Holyfield, Las Vegas
Tyson had blasted out all four opponents since his release from prison, while Holyfield started a 25-1 underdog after a poor performance in his previous fight vs. Bobby Czyz. Holyfield came through toe-to-toe exchanges to stop Tyson for the WBA belt.
5.11.1994: George Foreman W KO 10 v Michael Moorer
After losing his previous bout, Foreman uncorked a big right to finish Michael Moorer, 26, to be crowned world heavyweight champion again at the age of 45. Foreman had previously lost the world title, in another upset, to Ali 20 years previously.
28.11.2015: Wladimir Klitschko L PTS 12 vs. Tyson Fury, Dusseldorf, Germany
The Ukrainian's reign of nine and a half years as world champion was ended as Fury outboxed him for a unanimous points win. Fury's movement ensured the Ukrainian never got into the fight as the Briton won three versions of the world title.