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

Zverev has such great rhythm in his serve and is serving this set at 75% in and, if you consider the speed of those serves, it is an impressive statistic.

He has a huge amount of confidence.

Zverev gets things underway with his fastest serve of the day, Nadal unable to get his racquet on it.

Nadal gets out the serve but Zverev is up at the net, trying to draw Nadal forward. It's a real tussle but it's Nadal that snaffles the point with a smashed forehand. 

He skews his return to the next shot, though and that gives the German the advantage.

Genuine aggression from both players but Zverev has the better control, as Nadal tries that floaty backhand and gets the angle all wrong. 

Zverev can't control the next shot that comes his way, and two forehands are overhit before he gives the next rally an absolute blazing. Stunning stuff, well directed and it's Nadal that comes off worse as his reply ends up in the crowd.

Nadal responds with a body serve, Zverev comes forward and slices his backhand into the net. Point to Nadal, and it's tie-break time.

"Rafa, can I have your babies?" shouts a man in the crowd, drawing a plea for quiet from the umpire. Nether player takes the slightest bit of notice as Zverev works a lovely backhand beyond Nadal.

The ace comes whizzing down and Zverev rattles to a 40-0 lead, before a forehand slam holds his serve. It took him just over a minute to blast his way through that service game.

Image source, Reuters

John McEnerney: Rafa needs a full shot workout if he's going to have a crack at this title. His experience should see him through in four. Vamos Rafa.

Nadal goes for the big forehand but overdoes it, before grabbing back a point with a lovely, flighted backhand that Zverev nets.

There's plenty of spin on Nadal's serve and Zverev can't get the angle right. Nadal hands him a gimme as a forehand cuts into the net, and then bam. There's the ace. All level.

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

You get back what you put in and Johanna Konta is working so hard on the training court and the match court - she is a model player.

She is very difficult to get the ball past and she was able to match Caroline Wozniacki for consistency but dominated her for power.

Johanna is certainly the favourite against Ekaterina Makarova.

Image source, Rex Features

Smiles all around as Nadal reviews correctly and wants the point. Umpire says no and so they replay, with Zverev striking his response to particularly powerful shot into the net.

His serve is genuinely quick though. Back-to-back aces have Nadal striding from side to side, looking fairly unamused, before he slices his forehand into the net.

The grunts have gone up a notch from Nadal but it's Zverev who gets the early point, standing and hammering a forehand past Nadal, before the Spaniard draws the error out of Zverev's backhand.

A double fault from Nadal causes a growl of irritation before an absolute stonker of a serve, sent into the sun, is missed by a mile by Zverev.

Nadal advances and Zverev takes him on, but Nadal's forehand swat beats him as he holds.

Big cheers for Zverev as that big serve beats Nadal, before Nadal bites back with a forehand down the line.

Another double fault, maybe a sign of tiredness, from Zverev annoys him but a lovely ace makes him a bit happier. Nadal then goes for the two-handed backhand, miscues it and the ball ends up in the bottom of the net.

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

It is fascinating to see Zverev at this stage of his career. It makes the German Davis Cup team much stronger to have both brothers playing so well.

He has a great range of movement. He is 19 years old and is playing at this level, it is really impressive and he is someone that everyone is talking about.

Remember Zverev's older brother, Mischa, takes on Andy Murray tomorrow. 

Zverev looks as though a good gust of wind would blow him over but there's plenty of power in that serve of his.

Nadal shows that he can serve with a bit of oomph too as Zverev's return goes well wide, before the German hits his forehand back of the net. He looks up to the sky and rolls his eyes.

A ridiculous shot from Nadal, somehow angling the ball to perfection as it bounces inside the line. He'll hold to love.

Mark le Huray: Extraordinary level from Konta making Wozniacki (former world no1 lets not forget) looking very, very average.

Stonking serve from Zverev to get him underway, drawing the error from Nadal but a double fault ruins his mood slightly.

He looks sharp at the net too as Nadal slices into the net, and he's charging around all over the place as Zverev works a drop shot to perfection.

Another banged in serve, Nadal's return hits the net, and he'll hold. Rod Laver, watching on in the crowd, has a smile on his face.

Nadal, bright pink trainers glinting in the sun, comes off the best of a long rally as Zverev hits his forehand into the net. There's a grunt of agitation from him, and he's not much happier when Nadal fires down a return that Zverev skews into the crowd.

Nice from Nadal, up to the net and the drop shot ensures he holds his serve.

*denotes next server

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

Zverev has such a big serve, and can back that up with ground strokes and that is why so many people are tipping him to get to the top. He needed that game and you could tell by his reaction of what that meant to him.

He lost the second set quite tamely but that game puts a statement out.

Every time Nadal looks to be in front, Zverev responds with a stonker of a winner. Nadal flights his backhand in to get the advantage but Zverev gives it a thwack and gets the advantage.

He throws the ball up high, crashing the serve down, and Nadal's lob lands long. He can hardly believe it, but there's a huge shout of "come on!" from Zverev.

Image source, Reuters

Plenty of animation from Nadal now as he forces two backhand errors out of Zverev. He's settled back into the game now.

There's a huge roar from the crowd as Zverev makes an error on his forehand and Nadal takes the game.

David Law
Radio 5 live sports extra commentator

There looked to be a little bit of anxiety about Nadal and the way he was carrying himself. He was broken easily at first. Now there's a conviction about him. He knows what he's trying to do and he's doing it. He's more in control now.

Zverev's brief drinks break has done him plenty of good. He has Nadal running around behind the baseline, smashing down a backhand winner that leaves Nadal sprawling.

An ace tidies up the game for the teenager. Over to Nadal.