So we will end the live text commentary there.

Thank you as always for joining us and for your comments. We will back in the early hours of Sunday morning as Andy Murray plays in the last 16 against Germany's Mischa Zverev, with that match starting at 03:30 GMT.

Another Brit, Dan Evans, is also in action on Sunday and plays France's Jo-Wilfried Tsonga from approximately 05:30 GMT.

It could be another wonderful day for British tennis so get an early night and set your alarms early. Until then, bye for now.

BBC Two

Earlier today British number one Johanna Konta advanced through to the last 16 after demolishing Caroline Wozniacki 6-3 6-1, and you can watch highlights of that and the other day six action on BBC Two from 15:05 GMT.

It will be well worth watching so don't miss out.

Rafael Nadal on his own form: "Being realistic every match is so difficult. Today was a big battle and I am so happy to be through. I was losing a couple of times in the fifth set. 

"I said to myself, today is the day, with this fantastic crowd, everything is less difficult. It was a very special day for me."

Image source, Getty Images

Rafael Nadal on his victory: "I won by fighting and running a lot. I think everybody knows how good Alexander is. He's the future of our sport and the present too.

"It's been a very tough match for me. I didn't start playing my best and I was not feeling very well because I was losing too much court. When I felt I was feeling better I had more time to control from the baseline.

"It was a close one but he deserved to play a little more aggressive than me. I had to fight for every point."

Leon Smith
Great Britain Davis Cup captain on Radio 5 live sports extra

Zverev should be very proud of himself. He fought really hard, got himself in that winning position. He'll have to learn from this.

Everyone can see the potential. His serve is fantastic, his backhand is one of the best out there. He's 19-year-old and can add to his game.

David Law
Radio 5 live sports extra commentator

Nadal has been pushed by the most prodigious of talents. But he's done it, he's in to the last 16. You'd have thought he'd won the title. That's how much that win meant to him. 

You'll be seeing plenty more of Alexander Zverev. He's got a standing ovation.

What an effort from Zverev. He is only 19 years old but in the end the fitter, more experienced man came through, just about. 

But Alexander Zverev is going to only get better and fitter in the future. Four hours six minutes is how long the match took, and in the end his body gave up.

Nadal needs two points for the win after an ace takes him to 30-15.

BBC Radio 5 live sports extra

So, tomorrow Andy Murray faces Mischa Zverev, brother of Alex. BBC 5 live sports extra will have full coverage of the match, which starts from 03:30 GMT.

Dan Evans is also in action tomorrow against Jo-Wilfried Tsonga from approximately 05:30 GMT.

Tennis Breakfast will also bring you the best of the action from the fourth round in Melbourne.

Now we are at the sixth deuce. A delicate drop shot from Nadal sees Zverev drag his aching limbs to the net, and he just about gets to the ball but Nadal is well positioned to move to another break point.

Twice he failed, but this time he takes it and that is a double break of serve. Nadal 5-2 in the final set, serving for the match. Zverev needs a miracle.

Image source, Getty Images

Zverev is hoping his cramp eases up, and he is showing great character to remain in the game. He has saved two break points, and has the advantage, before a perfect lob from Nadal brings us back to deuce.

Just to remind you, Zverev is 6ft 6in, so you don't have much room for error when trying to lob him.

Zverev has to go all or nothing now. He doesn't have the movement for any long rallies so he goes into a bit of swing-and-hope territory. He moves 40-30 ahead but Nadal, the wily campaigner, is making his opponent run / limp / hobble at every opportunity.

Nevertheless Zverev saves one break point courtesy of an ace. He gets a bit of luck with the ball hitting the top of the net but bouncing over to give him game point, but he can't take it.

Image source, Getty Images

This could be a very sad way to end what has been a wonderful match. Zverev has a little bit of rushed treatment, with a spray being applied to try to ease off the cramp.

But Zverev can hardly move and it is no surprise that Nadal wins the next game to love.

The heart and desire is there for Zverev, but the legs look to have given up.

BBC Radio 5 live sports extra

Want to listen in to the end of this ridiculously good match?

BBC Radio 5 live sports extra are bringing you commentary of the rest of this match, along with highlights from the rest of the day. You can listen by clicking the link at the top of the page.

Leon Smith
Great Britain Davis Cup captain on Radio 5 live sports extra

There was no signs of it until that last rally, where it looked like it was hurting him.

Clearly the stress and overall effort that he's put in to get to this stage is starting to eat into his reserves.

There's no doubt now that Nadal will make him move here. He won't give anything cheaply away to test his movement.

David Law
Radio 5 live sports extra commentator

He looks in terrible discomfort. And Nadal lost the battle there but he might have won the war.

Nadal pounces on the fact Zverev is struggling. He is limping around the court, trying to loosen his muscles enough to continue. But Nadal sends him scuttling around the court, with the teenager looking in pain every time he strikes the ball.

Unsurprisingly, Nadal takes the next two shots and he breaks again. What a terrible time for Zverev to be struggling. Is that the decisive moment in the match?

Image source, Getty Images

First break point. Saved. Second break point. Saved. Zverev is living dangerously.

A backhand clips the top of the net and gets a loud scream from someone in the crowd, but the ball stays alive and a 37-shot rally, yes, 37, ends with Nadal putting one in the net.

But wait, Zverev looks to be struggling with cramp. He can't have a physio break.

It is nervy times for both players and we are at deuce on the Zverev serve.

The German eases some pressure with an ace that leaves Nadal motionless, but Zverev, who runs round for a backhand, misjudges his next shot and it is quickly back to deuce.

That mistake seems to cause a moment of self doubt with another Zverev error giving Nadal a break point.

But not this time. A loose shot from the Spaniard means we return, once again, to deuce. Drama.