Josh Kelly, who competed in the men's welterweight event at 2016 Olympics, believes the Englishman is control...

Steve Bunce
Boxing pundit on BBC Radio 5 live at Bramall Lane

It's such high quality. The work is exceptional. Some of the stuff Spence put together was brilliant - it's what you put together on the bag, not in front of a huge crowd on the champion's home turf.

A straight right, with so much power, and an uppercut from Brook, which, admittedly, doesn't land fully, in the last 20 seconds of the sixth again give Spence some nervous moments. That is Brook's round, and that could be the one that shifts the balance in his favour. Can he build on that in the seventh?

Image source, Reuters

Brook catches Spence early in the sixth, the American has to take a step backwards and again the crowd roar gets louder.

But if the American is in trouble, it is only very momentarily and he can quickly regain his composure. Nevertheless, an encouraging sign for Brook.

The three-time world heavyweight champion Lennox Lewis gives his thoughts on the fight so far...

Steve Bunce
Boxing pundit on BBC Radio 5 live at Bramall Lane

Part of the problem with Brook's right hand - he's holding it so high. Is it to defend his damaged eye? That right is not working.

Another left uppercut from Brook finds the mark, but Spence throws a flurry of punches with Brook on the ropes near the end of the round. Luckily for the Englishman, and the majority of the home crowd, most of those blows are blocked.

Image source, Reuters

This could well be a classic, both look to attack, there's no sitting back and no breathers being taken.

A right hand from Brook lands on Spence's chin, but the American is unmoved.

Steve Bunce
Boxing pundit on BBC Radio 5 live at Bramall Lane

A proper fight. After 22 fights, Errol Spence is the fighter we've been told. Kell is having to extend himself. The pair are having to battle non stop.

I gave this round to Errol: It's 2-2.

It is tense and tight. We are seeing a lot of good work from both fighters, but neither of them have had the other in any trouble.

The Sheffield crowd seem to rise to their feet as one as their man lands cleanly with one, but there is to be no successful follow-up.

Brook's counter right-hands could be the key, but landing it is easier said than done.

Image source, Lawrence Lustig

Claressa Shields, an Olympic middleweight gold medalist at London 2012 and Rio 2016, has some advice for her fellow American...

Adam Booth
Former trainer of David Haye on BBC Radio 5 live

A very good round for Spence. I gave it to him for what he did at the start of the round. The American looked a little bit uncomfortable at the end.

Some advice from Kell's Brook's trainer Dominic Ingle at the end of the third: "Don't hit him to the body, hit him to the head."

It was a bad start to the round for Brook, but he still ensures a right hook to the head rocks Spence's head back.

Brook ends it well, but, for the first time so far tonight, that could be a round where the judges favour the American.

Image source, Reuters

We see some of Spence's best work so far in the early stages of the third. A couple of body shots find their target.

Steve Bunce
Boxing pundit on BBC Radio 5 live at Bramall Lane

It was a better and busier round for Brook. But Spence looks relaxed taking these punches. The American gave a wink to his corner.

I've got it two rounds to nil to Brook.

Two time WBO Champion, at lightweight and light welterweight, Terence Crawford shares his first round views...

Good work, side to side, from Brook, who is having a bit of success with rights to the body.

Image source, Rex Features

Spence, who has never fought out of North America, has to eat an early right hand and then a Brook uppercut.

But we know Spence is a tough character and this is going to be far from easy for Brook. On Spence's record is a fifth-round win against Chris Algieri, a fighter who went the distance with both Manny Pacquiao and Amir Khan.

Steve Bunce
Boxing pundit on BBC Radio 5 live at Bramall Lane

That was as technical, tight and tense as I expected it to be. Spence having to really think his way through. Kell looks like the man suffering from a lengthy time away from the ring.