Amir Khan
Former unified light-welterweight world champion on BBC Radio 5 live

It was a great round for Santa Cruz, he's picking his shots really well and those body shots are hurtful. You do feel those shots.

Frampton is slowing down a bit he needs to keep his work rate high and trade shots more.

I've got Santa Cruz leading by one but it's very close.

Mike Costello
Radio 5 live boxing correspondent in Las Vegas

This is hard, hard work for both men... but it's harder work for Frampton.

Another close round. This is a tough one to call. Thankfully that's not my job. The pair go toe-to-toe, Frampton landing a left as he goes closer to his opponent. But back comes Santa Cruz at the death, launching a barrage of punches as Frampton bobs and weaves on the ropes. Not actually sure any of those landed. On we go...

Amir Khan
Former unified light-welterweight world champion on BBC Radio 5 live

I give that round to Santa Cruz, I think he finished very strong, he put more pressure on, pushing Frampton back. 

He made Frampton miss a lot of punches when he's on his back foot and letting Carl throw, then coming back with a counter. His game plan is working, he was the cleaner fighter and won that round.

"Leo, Leo, Leo!" The Mexican contingent inside the MGM Grand are enjoying themselves. As is their man. Santa Cruz uses those long levers of his to keep Frampton at bay, his jab and counter-punching proving very effective.

Oh! Has Santa Cruz hurt Frampton? The Mexican leaps forward with the bell fast approaching, seeming to catch the Northern Irishman with a right - and then another. Frampton on the ropes, Santa Cruz ends on top.

Mike Costello
Radio 5 live boxing correspondent in Las Vegas

He merely got caught in a tangle of legs. Referee Kenny Bayless was quick to wave his arms and say 'no knockdown'.

Amir Khan
Former unified light-welterweight world champion on BBC Radio 5 live

I give that to Frampton, landing some good powerful shots, especially inside. He was letting go of some great combinations. If he sticks to this game plan he's got a great chance.

More punches are being thrown than a Saturday night in Doncaster town centre. Excellent.

Santa Cruz takes a swing early doors in round three, but blasts Nevada air rather than Northern Irish jowels.

Frampton goes on the attack, Santa Cruz responds by landing some of his own. Frampton hits the deck in the final few seconds - but it is a stumble rather than a knockdown.

Amir Khan
Former unified light-welterweight world champion on BBC Radio 5 live

A very close round to call, both fighters making each other fall short. I think Santa Cruz is boxing on his back foot more which I haven't seem him do.

One thing that's helping him is the body shots, he's putting some great shots into Frampton's abdomen. A great round by both of them so a hard round to call. I had it level.

Dafydd Pritchard
BBC Sport at the MGM Grand, Las Vegas

Frampton and Santa Cruz have picked up where they left off in New York last summer.

Both boxers have burst out of the blocks with a flurry of ferocious hits, inflaming an already volcanic atmosphere inside the MGM.

Now then. Santa Cruz comes out quickly as the third round bell dings, Frampton coming back midway through with a couple of combinations. Santa Cruz smiles. Frampton sits back again, just sussing out his opponent. The Northern Irishman pins his opponent into the corner, the Mexican responding with some quick counter attack. Tight.

Amir Khan
Former unified light-welterweight world champion on BBC Radio 5 live

Santa Cruz was walking back with a smile on his face knowing he won that round. He had more success. He's just making Frampton fall short a bit. Carl seems to be trying too hard to get those power shots.

Frampton made a few errors in the first round - and his corner tells him before throwing him back out. He doesn't get drawn in as much in round two, both men sitting back a touch more. Frampton tries to go expansive in the last minute of the round, Santa Cruz ducking and diving out of bother. Advantage Santa Cruz.

Amir Khan
Former unified light-welterweight world champion on BBC Radio 5 live

What a round that was, both came out like it was the 13th round from the last fight, a lot of punches thrown with a lot landing.

It was a tough one to call, they both caught each other with big shots but I think Frampton caught Santa Cruz with the cleaner shots.

Koba Fern: I've got the wee man in the 4th. Successful defence.

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Mike Costello
Radio 5 live boxing correspondent in Las Vegas

A very lively opening round, what more would we have expected here after that first fight?

Well, this doesn't disappoint! Nice early right hand from Santa Cruz in the opening minute, Frampton responds. Another slashing right hand comes from Santa Cruz. The Mexican's jab working well. Is that a mark on Frampton's mush? I think it is. A flurry of punches are exchanged in the final 30 seconds - what a tear up!

Dafydd Pritchard
BBC Sport at the MGM Grand, Las Vegas

It is deafeningly loud inside the MGM Grand, owing mostly to the fact that Carl Frampton's legion of Northern Irish fans have turned this famous arena green.

This is meant to be a home fight for Leo Santa Cruz, who is based in the neighbouring state of California, but there is no denying Frampton has the biggest and most boisterous following here.

Referee Kenny Bayliss has a few words with two fighters, a touch of the gloves and off we go!

Dafydd Pritchard
BBC Sport at the MGM Grand, Las Vegas

If you're after some Northern Irish celeb spotting, then Frampton-Santa Cruz II is the fight for you.

Snow Patrol lead singer Gary Lightbody is here at the MGM Grand in Las Vegas.

Rory McIlroy was at last year's first meeting between Frampton and Santa Cruz in New York.

Who else might we see tonight? Jim Magilton?