Anthony Joshua faces unified heavyweight champion Oleksandr Usyk in a must-win rematch on Saturday night.
A loss for Briton Joshua would be another massive blow to his reputation, while a win for Ukraine's Usyk could set him on a path to becoming undisputed champion, possibly even a meeting with Tyson Fury.
The fight takes place in Saudi Arabia, with live text commentary on the BBC Sport website and app from 21:30 BST.
Only a drastically improved performance will see Joshua reclaim the WBO, WBA (Super) and IBF titles he lost almost a year ago, with pundits and pros split on whether the once unbeatable heavyweight can gain revenge over the undefeated Usyk.
WBO junior-middleweight champion Natasha Jonas: "It's a fight AJ just can't lose. I think we'll see a different AJ. But Usyk is phenomenal and you can never bet against him."
Former two-weight world champion Carl Frampton: "I hope I'm wrong and AJ can do enough to win the fight, but I think he has to do it early. The issue with his engine could be a factor in the fight. The longer the fight goes on, the better chance Usyk has. AJ by knockout has to be early, but I also think Usyk can stop AJ. I think it will be difficult for AJ to beat Usyk on points."
Watch Usyk and Joshua weigh in before world heavyweight title rematchLightweight Adam Azim: "I'm going with AJ this time. I think he's more determined. He's training hard. It could be like [Andy] Ruiz II, but I think this time he has to push it on him rather than box him."
Super-welterweight Liam Smith: "It's a tough one but you have to edge towards Usyk. If Joshua puts it right on Usyk, I think he can win. Joshua has fought in Saudi before but I don't think the location makes a difference. The winner has to go on to fight Fury."
Boxing coach Dave Coldwell: "It's a huge ask for AJ but he has the physical attributes to turn it around. The problem is that Usyk has skills to negate that. AJ will always have the power and pop in his hand to end the fight, but he has to get off to a really quick start and stop Usyk from getting into a rhythm. If Usyk does get comfortable, he will be unshakable. I would say Usyk is the favourite but AJ is a live underdog."
Heavyweight Derek Chisora: "AJ better win. The whole nation is counting on him. We need him to win. You don't get it. We need him to win. If he don't win it means your paycheque goes down."
Middleweight Hamzah Sheeraz: "I hope and pray AJ does it because I'm a massive fan of the way he goes about it. But if you're talking from a boxing perspective, I do think Usyk is going to get the better of him again. But my support is with Joshua all the way."
Four-time world champion Carl Froch: "My prediction to be honest is a prediction that I don't even want to hear. I think Usyk beats AJ quite conclusively again - maybe even gets the stoppage."
Super-bantamweight Ramla Ali: "AJ will win this one. Like when he lost to Andy Ruiz, he made some changes, and I feel like he's doing the same again - he's making changes."
Heavyweight legend Evander Holyfield: "I'm not surprised [Joshua is the underdog] but the fact of the matter is they know they're fighting a little guy. That's what he does, dodge all the time. He'll get hit by a big shot, it'll probably be hard but he's got good defence. He moves real well. If you're going to bet your money on anything, it'll [be on the] little guy unless he gets hit by a big shot."
Heavyweight Joe Joyce: "I'd say Usyk will win again, but I'm not writing off AJ. He's got a puncher's chance. Let's see what he's been working on in the gym and if he's able to beat Usyk, the better boxer."
Win or lose: Bunce & Froch on what's next for AJWelterweight Conor Benn: "I might have to sit on the fence. You'd think in your head AJ should have the tools to beat him up, literally beat him up. But that's a mentality thing. He's working with Robert Garcia, but he's never worked with a heavyweight before. There's lots of question marks over him. But I will back AJ."
BBC 5 Live Boxing analyst Richie Woodhall: "I think Usyk will probably run out a winner on points. I do think Josh can win the fight. The only way Josh wins the fight is he stops him or knocks him out."
Boxing trainer Buddy McGirt: "They've both got something to prove. It's a toss-up. If I had a winner I'd let you know."
Super-middleweight Callum Smith: "I think it's a completely different fight to the first time round. I think we'll get a different Joshua, but I think we'll get a different Usyk as well. It's whoever's gameplan comes off. I think this one will be a little bit more exciting - I think Joshua will go for him a little bit more."
Matchroom promoter Eddie Hearn: "I want to see a dominant performance from Anthony Joshua - I feel like he's the best heavyweight in the world. I want to see him break down and fundamentally beat up the pound-for-pound number one."
Former British super-middleweight champion Paul Smith: "If I had to put my house on someone I think the safe bet would be Usyk. But I'm hoping Anthony Joshua will pull it out and stop him mid to late rounds."
Boxing trainer Ronnie Shields: "AJ is good in second fights. I don't think he's going to knock him out, But I think he's going to win a decision."
Former European super-bantamweight champion Spencer Oliver: "I think Joshua is going to get the job done inside six, seven rounds. I think he's going to catch Usyk."
