Rybarikova serves a 111mph serve - it's only her first service game.

30-15.

A poor attempted half-volley at the net results in punishment.

Muguruza adds to the pressure with a wrong-footed return from the back - break point.

And then... a double fault.

What a way to lose your service game - not good.

Jonathan Jurejko
BBC Sport at Wimbledon

Practice over. Johanna Konta laughs like she has just heard Jimmy Carr's best gag as she puts her racquets in her bag. The British number one is completely at ease, despite all the increased scrutiny - from the media and the public - going on around her.

Suited security guards tell the punters to stand to the side, ushering the semi-finalist through the crowds and back towards the locker room.

"Good luck Jo!" Several well wishers shout encouragement, with a huge round of applause seeing her off.

Image source, PA

John McEnroe
Three-time Wimbledon singles champion on BBC TV

Muguruza has a lot more experience than her opponent but I have noticed she is pretty well strapped up there around her leg. That could have an impact.

Tracy Austin
Former Wimbledon mixed doubles champion on BBC Radio 5 live

Muguruza likes the ball at waist level to dictate from the powerful groundstrokes on both sides but Rybarikova gets the ball into awkward places.

Muguruza to serve.

Rybarikova tries to catch the Spaniard with a lob but missed by inches. But then the Spaniard fluffs the next

Muguruza, with some strapping on her thigh, wins the next - putting pressure on her opponent by coming to the net.

30-15.

But hmmm. She comes to the net again and makes a hash of an easy volley after Rybarikova made a hash of a return.

Anyway, a good serve and a good volley at the net sees her hold.

They've called time - the play is about to start... but here's a bit of celeb spotting from earlier.

Those young enough to be young probably won't recognise the person on the left in the bottom photo. That's Dame June Whitfield who starred in 'hilarious' 1980s sitcom Terry and June.

She also appeared in Absolutely Fabulous, apparently.

The fella in the top photo with the questionable blazer is Justin Bieber. Actually it's Sir Cliff Richard, who is to Wimbledon like biscuits are to tea.

Image source, PA

Image source, PA

Image source, EPA

This should be easy for world number 15 Muguruza.

I mean, she's been here before and her opponent hasn't. Her opponent is also the world number 87 - that's only 13 from 100.

And...aaaaand... she wiped the floor with experienced world number eight Svetlana Kuznetsova in the previous round.

So is Rybarikova just turning up on Centre Court to make up the numbers?

Well, this is a player who was outside of the top 400 in the world as recently as March because of injuries.

Since then she climbed up the rankings and...aaaand...won two events on grass en route to Wimbers.

And another 'and' - she defeated the Spaniard on grass at Birmingham two years ago.

They've met four times on the WTA circuit - it's two each.

Billie Jean King
Six-time Wimbledon champion on BBC TV

Rybarikova has great hands and can break up the rhythm - can she break up the pace of Muguruza's pacy ground strokes?

Jonathan Jurejko
BBC Sport at Wimbledon

After winding up her session with some more crunching forehands, Johanna Konta sits back on a courtside chair and then turns around to repeatedly smile and wave to a particular photographer.

It's only her fella! Konta's boyfriend Jackson Wade, who works for the Lawn Tennis Association, gets the shot every snapper at court six wanted.

How's he feeling ahead? "Pretty good," he smiles. Then politely informs me that he has to do some work. Here are both of them in action...

Image source, BBC Sport

BBC Sport app users click on the link

Nervous Magdalena?

Image source, Rex Features and EPA

Thanks Matt Henry.

Hello. Saj Chowdhury here ready to take you on a journey full of great shots, line calls, a moody net cord, spectators shouting things thinking they're funny but in fact..., joy, tears and people in good attire.

Yes, this is the first Wimbledon semi-final of ... Wimbledon 2017.

• In the Slovakia corner we have no-time Grand Slam winner Magdalena Rybarikova.
• In the Spanish (with a bit of Venezuelan) corner we 2016 French Open winner and former Wimbledon finalist Garbine Muguruza.

Be very ready. Available to read, watch and listen to on every BBC medium you can think of.

It has been a pleasure kicking off this historic day but the build-up is almost done, we're nearing the start of the first women's singles semi-final.

That means it's time for me to hand over to Saj Chowdhury who will expertly take you through Garbine Muguruze v Magdalena Rybarikova.

Laters!

Piers Newbery
BBC Sport at Wimbledon

The Konta coaching team have been benefiting from their charge's relentless pursuit of excellence off court as well as on it, with the world number seven producing a daily baked treat for their analysis...

Image source, @Fitzmister

Jonathan Jurejko
BBC Sport at Wimbledon

Midway through her hitting session, Johanna Konta swigs from a bottle of water and glances up and left towards the ivy-covered facade of Centre Court.

She laughs. Something has caught her eye. Her coaching team - Wim Fissette and Andrew Fitzpatrick - look in the same direction. They laugh too.

What have they spotted? It appears to be the electronic scoreboard, flashing up today's order of play.

"It's me!" is what Konta might be saying. Because the British number one's face appears, alongside that of Venus Williams. their images below the heading 'Wimbledon semi-final'.

Perhaps a pinch yourself moment for the 26-year-old.

Image source, PA

This day has been 39 years in the making for us Britons so we want to know how you are watching today's matches.

Is your boss letting you watch in the office today? Or are you having to follow the play on the sly?

Perhaps you've got the set-up with a comfy seat, food and drink all sorted at home?

Send us a picture to #bbctennis on Twitter and we'll see who has done the best job.

Billie Jean King
Six-time Wimbledon champion on BBC TV

You don't want to ignore the nerves. What really helps is when you admit it. Saying 'I am fine' is the worst. Accept it and it dissipates and allows you to focus on the task in hand.

I keep thinking about how important this is for Konta but she needs to just stay focused.

Joanne Pen: Oh I love listening to Billie Jean King. She makes me feel like I could be a Wimbledon champion if I just focus 💪🏼🌱🎾

We believe in you Joanne - go get em.

Kim Clijsters
Former world number one on BBC TV

When I was a junior, Wimbledon was like Disneyland seeing all the great players walk past you! It's still special to me.

It's a huge occasion. It starts after the quarter-final - the media hype it up.

For Johanna, it will be nerve wracking but it will be for Venus too. Just because she has been here before won't make her day any easier.

Image source, Getty Images

And don't be fooled into thinking this run from Venus is some sort of fluke in the final years of her career.

She is the 10th seed in this year's championships and reached a Grand Slam final at the Australian Open in January, only losing to little sis Serena.

Venus also reached the semi-finals here last year before defeat to Angelique Kerber.

That said the American is the oldest player to reach a Grand Slam semi-final since Martina Navratilova at Wimbledon in 1994.

Will that influence today's match?