Sonia Oxley
BBC Sport at Wimbledon

Even a Serena mis-hit is so powerful it takes two people in the Royal Box to attempt to catch the ball after it rattles off her racquet. Eventually it is retrieved by one of the stewards.

Image source, Reuters

These two are very different in their styles, despite both being hard hitting. Giorgi is short but bounces around on her tip-toes at the back of the court like a gymnast, as Sam Smith says on commentary.

Giorgi has started well. More bounce to get into the net and then with fast hands she whips away a forehand volley.

Serena Williams lays down a marker to her opponent. 'It's not just you who can whack down some serves.' A hold to love.

Image source, Getty Images

Julia Gorges is returning well on the second serve. A fizzing cross-court forehand was a highlight of that last game.

Kiki Bertens clings on though to hold. Competitive start to this match on Court One.

Jonathan Jurejko
BBC Sport at Wimbledon

Quite a few empty seats on Court One as ticket holders scoot downstairs for a lunchtime treat.

Image source, BBC Sport

With just seconds between the conclusions of Ostapenko v Cibulkova on One and Kerber v Kasatkina on Centre, the gangways in both courts were full of slow moving traffic.

Nice from Camila Giorgi. Centre Court hums in delight as the Italian hits a winner to see off the break points. Now two big serves. A good hold to start. That should settle her in her first Grand Slam quarter-final.

Serena Williams makes an ominous start, nonchalantly landed a forehand onto the baseline on the very first point for a winner.

She misses the next two but then at 30-30 Giorgi double faults.

Here's a break point for Serena in the first game.

Chanda Rubin
American former world number six at Wimbledon

It is very dangerous to already write Serena into the semi-finals, especially with such a tricky opponent as Giorgi is.

Serena has won 18 matches in a row at Wimbledon, having won the tournament in 2015 and 2016 and then missing last year when pregnant.

Will today be an upset or number 19?

Image source, Getty Images

Billie Jean King
Six-time Wimbledon champion on BBC TV

The further she gets in the competition - watch out. Serena plays herself into competitions, you want to play her in the first and second round because she gets better every match.

She is such an amazing athlete, she is so strong emotionally and mentally. She is pure power and has the most beautiful serve. It is poetic, the motion is perfect.

When she gets in a tight situation her serve comes through every time.

Image source, Getty Images

Serena Williams has played four matches so far in this and three of those players were ranked outside the top 100.

World number 52 Camila Giorgi will be the highest-ranked player she has played so far this year's tournament.

Chanda Rubin
American former world number six at Wimbledon

Giorgi has two settings: fast and faster, She hits every ball so hard. She is getting better at getting a sense of the moment and making balls at critical moments. She has improved and will be a challenge to Serena.

We talk about how much Serena has played and improved, but I think she is not at full throttle. It will be a battle of who can get on returns when the other lets up on serves.

Angelique Kerber after her win over Daria Kasatkina:

"I was expecting a tough, close match. She was tough, we have played a few times, so I was trying to take in point by point. At the very end we played at a high level. I was trying to stay focused during my serve. It is great to be in the semi-finals.

"She played very well, moving me a lot. At the end I was not thinking too much. It is not match point, I was just trying to play another point. I was trying to push myself to the limits.

"I don’t care who I play next, we are in her semis and you have to play your best. I am looking forward to playing the semis and playing good tennis."

Serena Williams and Camila Giorgi make their way onto Centre Court.

I doubt there'll be many long rallies like in the last match.

These two like to give it a whack.

Netherlands' Kiki Bertens has already knocked out two giants – Venus Williams in the third round and Karolina Pliskova in the fourth, who was the only remaining top 10 seed.

But she will be competing in her first Wimbledon quarter-final.

She reached the semi-final of the French Open in 2016 and enjoys most of her success on the clay court.

The 20th seed will face a different challenge today when she takes on former doubles partner Julia Goerges.

German 13th seed Goerges is also competing in her first Grand Slam quarter-final – the furthest she has reached is the third round.

In fact, she hasn’t even progressed beyond the first round at Wimbledon for the last five years. The only seeded player she has met on route to the quarter-finals was 23rd seed Barbora Strycova.

Serena Williams has Wimbledon singles title number eight in her sights.

Today's challenger is Italian Camila Giorgi, appearing in her first Grand Slam quarter-final.

Next up on Centre...

Image source, Getty Images

John McEnroe
Three-time Wimbledon singles champion on BBC TV

It was a crazy, awesome, exhausting game for both. If Kerber lost I would have backed Kasatkina to win after what she had been through.

Kasatkina kept battling to her credit but could never get in front. A heck of a way to end that match.

Sonia Oxley
BBC Sport at Wimbledon

Wow, a standing ovation on Centre Court after some truly fantastic tennis at the end of that Kerber match.

Under pressure Kasatkina delivered delicious drop shots and angles that saved match points - and one rally even had fans on their feet. But in the end it was not quite enough.

Serena Williams is up next here but somehow I don’t think we’ll see rallies as long as the ones we have just seen here.

So it will be Jelena Ostapenko against Angelique Kerber in the Wimbledon semi-final on Thursday.

Who are you backing?