That makes the stakes at the O2 Arena in London, and live on DAZN, extremely high for Joshua (25-3, 22 KOs).

For Helenius (32-4, 21 KOs), a late-replacement opponent, an upset victory would open doors to another huge fight and payday.

That being said, DAZN lists its keys to victory for both fighters:

Robert Helenius' keys to victory

Disciplined pressure

Go back and watch Robert Helenius take on his former sparring mate Deontay Wilder last October. Helenius pressured and at times was reckless with his forward fighting — so much so that it left him susceptible to a short right hand and a scary first-round KO loss.

We all get that Helenius will be going for the upset and really has nothing to lose as a late-replacement opponent. But against another heavy-handed fighter like AJ, Helenius can't afford to walk Joshua down recklessly. Despite this situation, Helenius must pressure with discipline. Otherwise "The Nordic Nightmare" could find himself flat on his back and reliving a nightmare.

Unleash those crisp one-two combinations

The veteran heavyweight has an effective one-two combination that lands stiff and crisp. He sets it up with a long left hand to which his straight right explodes right through in hurt harmony. Helenius would be wise to assert this weapon early because if he's able to split Joshua's guard with it, he can keep using the combination to set up some more damaging hook attempts soon thereafter.

Up the volume toward significant output

As long as Helenius is disciplined with his pressure and able to pull off those combinations early, as aforementioned, he should then look to up the volume a notch.

Increasing his punch count can possibly throw Joshua a bit off for Helenius to land something impactful enough to shock the former unified heavyweight champ. But that's going to be a very tall order considering 22 of Joshua's 25 victories have come by the way of knockout. Still, Helenius has to go for it whenever he feels fit.

Anthony Joshua's keys to victory

Assert the power jab first

Joshua touching the taller Helenius with a power jab in the opening round would bode really well for the British fighter to open up his offense further.

That's because Joshua's jab often carves out space and puts his opponents on notice of his glaring power. It creates instant respect upon landing and it may back up and thwart Helenius enough to think twice before fighting forward and unleashing for an upsetting knockout blow.

Use Helenius' aggression against him by measuring counterpunches

After some tense words exchanged during the weigh-in Friday, Helenius declared that he's here to pull off the upset.

That could produce a Helenius demonstrating a go-for-broke, nothing-to-lose style that's ripe for the picking for AJ. If Joshua senses that urgency from Helenius early, it's up to him to sit back and measure the Finland fighter up and timing pounding counterpunches that leaves the veteran reeling and ends his night.

Load up on that uppercut

Joshua told DAZN how much he and trainer Derrick James were working on that uppercut. 

Well, it seems to be tailor-made to detonate on a taller Helenius who often shows lapses in his guard, especially when trying to generate offense.

If Joshua can sit on his back foot — which is where Wilder knocked Helenius out — and be patient, he could time that crunching uppercut that finishes "The Nordic Nightmare" and inches him that much closer to a showdown with "The Bronze Bomber."