The fifth is underway. I'm wondering what Kell Brook is thinking from his ringside seat.

If Khan were to be humbled, surely the appetite for a fight between the two would disappear.

But Amir Khan is all out attack early in this fifth as he backs his man up to the ropes with a flurry of heavy shots. Samuel Vargas in trouble, the crowd up screaming for more...

Image source, PA

"You have seven more rounds, take your time, keep banging them out," says Khan's trainer Joe Goossen.

The bell ends the fourth and in the final minute Amir Khan soaked up a right hand but went on the attack himself. Again, as has been the case throughout his career, he looks like he can be tagged too easily.

In some ways though, is this the fight he needs? That time in the jungle, the easy win over Phil Lo Greco, this is a different ball game.

Good, fast work by Khan early in the fourth and he digs a nice shot into the body which stops Vargas in his tracks.

A good jab by Samuel Vargas gets through and rocks the head of the home fighter briefly.

Around 90 seconds of the fourth to go...

Amir Khan did well to walk through that storm in many ways and returns to his stool with a composed look thanks to that second knock down.

What a fight so far. Who is your money on?

Image source, Getty Images

Tony Bellew reacts to the second round knock down for Amir Khan

Amir Khan gets the knock down this time. This is like a game of tennis as proceedings flow back and forth. In truth, that one is a bit dubious as it looked like it was on the back of the head but the referee counted it so the momentum returns to the British fighter.

My oh my. Samuel Vargas will be feeling so much better. That right from range landed sweet on the chin and Khan in truth was lucky it came seconds before the bell.

Round three is underway and Khan needs to evade trouble for a minute or two you would think...

"You were too calm in front of him and he is still dangerous," says Amir Khan's trainer Joe Goossen in the corner.

Some blood trickles from the nose of Samuel Vargas. The water he is in is not yet deep enough to consume him but it's shoulder height for sure.

And WOW.... a knockdown for Vargas with an overhand right. Khan hit the deck like a sack of spuds but springs back up.

What is happening?

Image source, Reuters

Amir Khan cannot miss. Each time Samuel Vargas attacks he ducks low when he's got his shots off and Khan is just picking him off at close quarters with rapid hands.

Vargas is just trying to steady himself after that knockdown. He looks like he has bought some time but is Khan just waiting for another opening?

Early action and Amir Khan has his man down. The hand speed is just too much and a left hook sent Samuel Vargas down...

Image source, Reuters

A fast opening minute where the jab is king for both men. The pace slows a touch. Samuel Vargas is covered in body art front and back. He bobs and weaves but gets in too close and Khan gets two shots off, finishing with a right hand up close. Again he goes in for some action and gets it wrong, sucking a left hand from Khan who will not turn opportunities like that up.

A minute to go and Khan wobbles his man sweetly with a flashing right hand. Vargas looks back and shakes his head but he felt that, don't you worry. Brilliantly quick hands from Khan in the corner as a left hook lands when Vargas dives in.

Khan's round all day long and those hands look rapid.

Image source, Reuters

We are off and running, a last prayer for Khan seconds before the bell.

Samuel Vargas looks to get the jab off to the body early on and Khan responds with a couple of his own, one lands nicely. That hand speed catches so many out early on....

Mr Michael Buffer demands we get "ready to rumble" and somehow that slogan never gets olf does it.

He turns to Samuel Vargas who takes a sip of water as his name his read. His t-short is removed and shows us some impressive body art.

Amir Khan bounces on the spot, his 37th professional bout is seconds away.