Maybe Nadal read my post saying he was struggling 15 minutes ago. He's upped his level again and now is beating all of the fluff off these tennis balls.

But Del Potro isn't going home from this party. He can still whack them and does so to get to 30-30.

Rafa takes the game though and celebrates with not one, not two but three fist pumps.

Rafa never ever gives in.

Del Potro slips and can't get himself back in the rally.

He slams the ball down into the turf in frustration.

Nadal has the break.

Andy Murray
Two-time Wimbledon champion on BBC TV

Image source, AFP

Nadal's body language is impressive. 3 hours and he doesn't stop moving, fist pumping, looking up to his box all the time. It is great to see.

Nadal is back on the hunt. Del Potro nets on the forehand. 0-30.

And now wide with the usually rock-solid on the forehand.

Three break points Rafa...

That's a better game for Rafa Nadal. He holds to love and pumps the arms and tries to get himself going. He's always going to be playing catch-up in this set though. That never helps.

Image source, Getty Images

More ferocious serving from Del Potro. He holds comfortably. Rafa had three set points in the second remember. He's struggling here.

Goran Ivanisevic is still in his seat watching his charge Milos Raonic rather than his nation Croatia in the football World Cup semi-finals.

Focus.

A hum goes around Centre Court. There has been a goal and the crowd know it.

Thanks for the thumbs up guys. It's good to know there's still someone there. Centre Court is still pretty full despite events in Russia. There are a few empty seats but they could be people who nipped out at the end of the set.

Juan Martin del Potro's wrists have spent plenty of time under the surgeons knife over the years and worryingly he is shaking the left one.

Juan Martin del Potro starts confidently by racing to 40-0 but then falls asleep. He puts one backhand long and then double faults.

Nadal doesn't give in! He leaps to his right, diving to the grass Boris Becker-style, making the crowd scream in delight but he puts the follow-up wide.

DelPo holds.

Image source, Getty Images

Rafael Nadal comes jogging back onto court after nipping off at the end of that set.

Here we go in this fourth set.

If you're still following this rather than, or as well as, the football then give me a thumbs up below.

Andy Murray
Two-time Wimbledon champion on BBC TV

Credit to Del Potro. On that set point, I wanted to see when he had the opportunity on the forehand to go big. He went big. That's his game and he plays his best when he takes those opportunities with big tennis. He deserves to be 2-1 up.

Right then. This is either a four-set victory for Del Potro or we're going the distance.

There's a football match about to start - which you can follow here - but don't worry tennis fans, we're not going anywhere.

Another missile from DelPo! How do you play that? Juan Martin del Potro takes a 2-1 lead.

Is the world number one following Roger Federer out of Wimbledon?

It's heart in mouth stuff but eventually Del Potro puts away a smash.

THREE set points for Juan Martin del Potro.

Del Potro finds the baseline with a missile-like forehand. 0-15.

Nadal serves and volleys but dumps the ball into the net. 0-30.

Here come the crowd in support of Rafa...

Centre Court is always a quiet place mid-rally but when Del Potro winds up for the forehand everyone seems to hold their breath, knowing something explosive is about to come.

Nadal gets to 30-30 but then misses a second serve return, much to the Spaniard's frustration.

DelPo sees off the challenge. Nadal must hold next.

Image source, Getty Images

Tim Henman
Former British number one on BBC TV

In the last couple of games it looks like Nadal is trying to finish points at the net. When he sees Del Potro go for the slice he is looking to move forward.

Juan Martin del Potro is now on the difficult side of the court, running from sunshine into shade. Nadal is pushing the big Argentine back in the court with his vicious top spin and then throws in the drop shot.

Now Rafa is even rushing into the net. You don't see that too often.

We've had one huge shock in the quarter-finals here at Wimbledon.

Here's the moment South African Kevin Anderson knocked out defending champion Roger Federer in a marathon match.