Tyson Fury can ill afford to have an off night against Otto Wallin on Saturday on ESPN+, as he needs a victory to set up a rematch with Deontay Wilder. The consequences of an upset would be disastrous for Fury, but lucrative for Wallin.

What if Tyson Fury loses?

If Fury needs a reminder of how costly defeat in a warm-up fight can be, he should take a look back at the career of the boxer for whom he was named after: Mike Tyson.

Fury has already claimed he is due to face WBC world heavyweight champion Deontay Wilder in a rematch on Feb. 22, after their points draw in December, but must first get past Otto Wallin in a non-title bout at the T-Mobile Arena, Las Vegas on Saturday.

This fight should not pose any serious trouble for Fury, but if he has under prepared then all those future plans are in danger of being becoming as costly as an unlucky night at a nearby Vegas casino.

Wallin (20-0, 13 KOs), of Sweden, comes with an unbeaten record but the 28-year-old has not fought at anywhere near the top level. Fury (28-0-1, 20 KOs), 31, from Manchester in England, starts as a big betting favourite but upsets happen, and defeat would be disastrous for the former champion as well as for fights fans eager to see more big matchups in the division.

American Andy Ruiz Jr (33-1, 22 KOs) was a former world title challenger, and was an accomplished amateur, but his stoppage of Fury’s English rival Anthony Joshua for the IBF, WBA and WBO world titles was a big shock, the biggest at heavyweight since Fury out-pointed Wladimir Klitschko for the same belts in November 2015. Joshua (22-1, 21 KOs) had talked excitedly pre-Ruiz of potential unification fights later this year, or next, against either American Wilder or Fury. But now, we must wait and see if those matchups can realistically happen with a major title on the line.

Joshua gets the chance to redeem himself in a rematch, in Saudi Arabia ‪on Dec. 7, but upset wins can wreck careers and deprive fans of the fights they had been yearning for.

Just take a look at how three upset losses shaped Tyson’s career.

Tyson will be remembered as one of boxing’s best world heavyweight champions in a career that saw him become the youngest undisputed world heavyweight champion aged 20 in 1987 with two reigns as a champion (1986-1990, 1996). But he was also victim of three big upsets, which scuppered big fights and plans.

Tyson’s career ended, aged 38, when he was stopped by Ireland’s limited-but-game Kevin McBride in 2005. Tyson cut a desperate figure, labouring and fouling his way until he finished slumped in a corner.

By this stage, Tyson was fighting to clear some of his mountainous debt but there was still pre-fight talk of a title shot against Vitali Klitschko, Chris Byrd, John Ruiz or Lamon Brewster.

In Tyson’s previous fight a year earlier, England’s Danny Williams overwhelmed Tyson with a fourth-round ambush in Louisville, and this fight truly costly for the American.

Williams was better than McBride and Wallin, a former British champion, but he was selected by Tyson’s team because they reckoned he was the perfect, obliging warm-up opponent. It is the same theory for Wallin.

Williams came in off the back of two stoppage wins, but before that had lost his British crown to Michael Sprott on points in their third encounter, and was himself stopped a year before by Turkey’s Sinan Samil Sam for the European belt. Williams had sketchy form, even if he had mixed at good level, but Tyson was crucially exposed when put under sustained pressure in round four.

Some argue that Tyson ceased to be a serious heavyweight when he fell apart against Buster Douglas in 1990 in Tokyo, Japan. Douglas was a 42-1 underdog, and Tyson was so expected to win that his next fight against Evander Holyfield had already been announced for later in the year, with Tyson guaranteed an unprecedented 22 million. But Douglas stopped Tyson in the tenth to ruin those plans to become undisputed champion.

Fury is not at the same stage in his career as Tyson was against Williams or McBride, but if he has been lacking in motivation during his preparation, taking some shortcuts, which culminates in a huge upset, then he can kiss goodbye to the Wilder rematch and hopes of facing Ruiz or Joshua in the next 12 months.

Fury will have to rebuild and repair his career, which will endanger his US television contract and would be an indisputable blow to his market value.

What if Wallin wins?

If Wallin pulls it off, it will be the greatest win by a Swedish boxer since Ingemar Johansson — the nation’s best ever boxer — stopped American Floyd Patterson for the world heavyweight title in three rounds in 1959.

Due to the gulf in experience with Fury, it would be an even bigger shock than Ruiz beating Joshua.

Fury would be left embarrassed by a defeat that would see the second seismic shift on the heavyweight scene this year after Joshua’s loss to Ruiz.

Victory for Wallin would probably mean a rematch, rather than the Swede progressing to face Wilder, who would prefer a higher profile opponent and instead try and negotiate a fight with the winner of Ruiz-Joshua.

Wallin, if he pulls of the upset, will become the chief instigator in setting up Wilder versus Ruiz or Joshua for all four world heavyweight titles in 2020.

If Wallin loses, where does he go from here?

Defeat against his best opponent yet will not be a crushing blow for Wallin — few expect him to win in Vegas — and he would revert back to fighting around Scandinavia.

The exposure of this weekend will also help Wallin — win or lose — gain bigger pay days against better-known opponents too, especially if he gives a good account of himself.

Challenging for the European title, and winning it, is a route that would propel Wallin back into world title contention if pulls off an upset on Saturday.