A quieter round for Crawford, perhaps collecting himself before a big finish.

Spence is determined to show he is still there fighting but Crawford works the jab well once again, landing the more telling hits.

How much longer can Spence hang on? He's been sent down three times now in this fight but the bell goes and he's not out of this just yet.

On we go to round eight.

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Credit for Spence to still be going. He's been sent down twice in this fight but is still going. It feels to be pride more than anything else, such is Crawford's control of this fight, and he's down again!

Spence must know this is running away from him and he's aggressive from the start of round seven, but still Crawford keeps his cool, biding his time and then floors Spence again with a thunderous right hook!

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Spence has been urged to try and close the gap by his corner and he's trying to do just that in this round but he's looking tired and we're only at the midpoint of the fight.

Crawford connects with a fierce right hand and Spence backs off, but then walks into another big hit before Crawford finishes off another strong round with an uppercut.

Crawford feels to be going up through the gears and as Spence misses with a jab, Crawford responds with a fierce left-hand counter.

There's definitely a look of concern on Spence's face as he knows this is starting to slip away from him.

Crawford takes full advantage of a mistake by Spence as he lands a couple of powerful jabs before then glancing his opponent's chin with an uppercut.

Spence needs something, anything to feel he is in this and he finds it with a big left hand that prompts "oohs" from the crowd just before the bell.

Still, another round for Crawford.

There's some damage to Spence's face evident early in round four. Terence Crawford is landing some bruising hits on the counter, particularly with the left hand.

Suddenly caution turns to aggression as Crawford unloads with some quality hits midway through round four.

Spence needs to be careful here, he tries to unload a few himself but walks into a left hand from Crawford, who comfortably takes this round.

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Spence lands a good right hand early in round three - crucial he provided a response to show his opponent he is still in this.

He throws a few hits to the body, looking for Crawford to drop his guard. Spence is attacking low and that leaves him open to the counter, and he gets caught square by a good left hand on the counter.

Spence is leaving himself far too open in his attempt to assert control and Crawford catches him a couple more times on the counter but Spence takes them and finishes strongly.

A tight round, maybe just going Spence's way. Just.

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Spence is back on his feet but Crawford senses blood and he launches an attack. The crowd is bouncing and almost drowns out the sound of the bell, which will come as welcome relief for Spence.

There's the fireworks!

Spence had the better of the first round but Crawford looked pretty relaxed throughout. Spence is on the attack again early in round two with Crawford yet to get going.

Spence remains on the front foot but Crawford is doing a good job of blocking his jabs before then countering well with a combo. He follows up soon after with a good right hook and the crowd starts to get going as Crawford unloads for the first time in this fight... and then a big right hand sends Spence down!

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No fireworks from the off, both fighters taking a relatively cautious approach, testing each other out.

Both throwing jabs in the main early doors, Crawford landing a decent one midway through.

Spence is the aggressor in the closing stages and a jab to the head gets through just before the bell.

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It has been years in the making but finally the bell goes for round one of what could be one of the biggest fights of this generation.

It is a really good cheer for Errol Spence too, his supporters certainly making themselves heard.

The two fighters touch gloves. Here. We. Go!

Terence Crawford definitely has the bigger support here, his name getting the louder cheer as it is announced.

All that matters is what happens in the ring, however.

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Coral Barry
BBC Sport combat sports editor in Las Vegas

The T-Mobile really lost their mind when Eminem appeared. You've really made it when Eminem is your hype man.

The arena is now almost completely full and it's the calm before the storm.

Just got to sit through the American anthem and we're ready to go.

Those entrances have really got the crowd going and the atmosphere is bouncing now as the two fighters are introduced in the ring.

Steve Bunce
Boxing expert

I think it might come down to who's the smartest. Some people are convinced that's Spence but I think Crawford might be smarter. The main unknown about this fight is who's got the most left in the tank. I've just got a feeling it might be Crawford. But even though I'm favouring Crawford, I would be stunned if one of them walks away with this fight. I'd be absolutely amazed if there's one master.

Errol Spence Jr is undefeated in 28 fights, with 22 knockouts, while Terence Crawford has a perfect record from 39 professional fights, winning 30 of them by knockout.

Crawford has beaten Britons Ricky Burns, Amir Khan, Kell Brook along the way, while Spence has also defeated Brook.

Whose unblemished record will be ended tonight?

Terence Crawford's rapper I do know! Eminem announces Crawford's name and that gets a huge cheer before the two walk out to the ring.

What an entrance.

First out is Errol Spence, lead out by a rapper. I apologise if he's uber famous but my rapper knowledge is pretty limited but its got the crowd going for sure. He's looking super calm.

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