Chanda Rubin
American former world number six at Wimbledon

Serena's serve is one of the best serves in history in terms of the women's game. I know because I have faced it! She can hit every serve to each spot in the box. Then you see the way she returns it's very intimidating for players. She is so confident. She is so solid in every aspect of her game. I think her coach told her not to limit how much she can win and she has taken that to heart.

Kim Clijsters
Four-time Grand Slam champion

Venus will not try and not give Kiki any presence out there. Try and stay in this, keep the unforced errors down. If Kiki comes up with great points then fine, but let her win it. Don't give it too her.

I must apologise to all Dutch tennis fans reading this. I accidentally called Kiki Bertens Belgian earlier. She is indeed Dutch.

Regardless she's looking good for one of the biggest wins for her career here. She's only ever reached the fourth round of a Grand Slam three times. Will Bertens show signs of nerves?

Just two more holds of serve needed.

Serena's opponent today is France's Kristina Mladenovic, the world number 62. She saw off Germany's Tatjana Maria in the last round.

Saj Chowdhury
BBC Sport at Wimbledon

Tejas Teladia from London (right): "I think both Federer and Williams are in the top 10.

“Roger has won so many Grand Slams and continues to play at such a high level.”

Image source, BBC Sport

Chanda Rubin
American former world number six at Wimbledon

It's an incredible story for Serena WIlilams that, with the changes in career with and becoming a mum now, she still has that desire. I have no doubts she will get back to her top level again. She has gone toe to toe with these players so far and seen them off.

A hold for Venus. If that's the last bit of this match Serena sees from the locker room before going out on Centre Court then she'll have a little bit of hope her big sis can still progress.

Venus needs to find a way to break this Bertens serve though.

Image source, AFP

It is 1469 days since Serena last lost a match at Wimbledon.

That was way back in 2014 when she was surprisingly knocked out by Alize Cornet.

Since then she has won the title in 2015 and 2016 before missing last year's tournament due to pregnancy.

In total the American is unbeaten in 16 matches going into her match on Centre Court today.

She's up next.

Serena Williams has made decent progress in this tournament as far as she continues her comeback following the birth of her daughter.

She struggled at times in her opening match but looked dominant against Viktoriya Tomova in round two, saying afterwards she feels as though she is going in the "right direction".

Today she faces her biggest test yet against former top-10 player Kristina Mladenovic.

"I haven't played her in a while," Williams said.

"She's had a really good year last year. She's still doing well. I have to come out there and do the best that I can do."

Venus is is grunting and groaning. She's in serious trouble. Bertens holds with ease.

Her sister Serena will be stepping out on Centre any second now...

That was something else from Gael Monfils.

The Frenchman was a set down having had a medical timeout, but turned it around with some scintillating tennis - talk about magic sponge. Reckon he was desperate to get off and watch France's World Cup quarter-final against Uruguay?

Here he is: "I slipped a bit, think I pulled my groin a little bit. It was a bit tight, the physio loosened it up. The physio told me I could go for it, so I was not worried about my leg anymore.

"I tried to serve well, dictate the point with my forehand, reach his serve as much as I could and put it deep.

"I am very happy. A long time I have been chasing (to reach the fourth round). Allez le Bleus!"

Kim Clijsters
Four-time Grand Slam champion

When you win to go up a break in the second set, you are still no where close to winning but it gives you the feeling the momentus in on your side.

But Venus Williams can't hold Kiki Bertens out! The Dutch player comes back and leaves Venus sprawling at the net.

Venus now trails by a set and break.

If she goes out only two of the top 10 women's seeds will be left.

Ooooooooos and gasps from the crowd. Venus dumps a sitter into the net. 0-30.

Now is that 0-40? The American's forehand has been called out.

She challenges.

In by a whisker. In fact it's only half a whisker.

Image source, BBC Sport

Made it!

That's a crucial point for Kiki Bertens. Venus Williams rushes to the net but Bertens places a lob flush onto the baseline to win the point. She needed that. Venus was on the hunt for a break of service.

Instead, the Dutch player holds. She shrieks in celebration.

Image source, Getty Images

Sam Querrey flat bats Gael Monfils' return into the gutter.

The Frenchman has the chance to serve for the match. He's a double break up.

That must be the first Gael Monfils miss we've seen in a long time, tickling a backhand into the tramlines.

The Frenchman wrong-foots Sam Querrey with a corker right out the heart of his paddle that skips down the middle to make it 30-30.

Querrey goes long on the next exchange... break point.

Venus lost the opening set against Johanna Larsson in the first round and in her second round match with Alexandra Dulgheru so she has experience of winning from behind.

In those two wins she dominated the second and third sets, only dropping four games across the four sets.

She starts this one against Kiki Bertens with a hold of serve.

Sam, Sam, Sam... the American misses a sitter after being handed the opportunity by a poor Gael Monfils drop shot.

Querrey remains a break down in the fourth set, and can't be passing up chances like that.