Jason Smith: There’s very few players I’d stay awake til 3am to watch a tennis match but Emma Raducanu is one, GO GO Emma!

Here's what an ice-cool Emma Raducanu had to say just before heading out to the court.

On playing eight matches so far including qualifiers, she said: "It's very helpful to have had this many matches, they've helped build confidence in my game."

And on tonight's match: "To play on Ashe in a night match under the lights is one of the most iconic things in tennis. I can't wait to get out there. I'll just be focusing on myself tonight."

Alex Larder: I’m up in 3 hours for work but this will (hopefully) be so worth it!

Tom and Barry: Stayed up all night for this, 8.30 calls will be slightly cloudy, but will be worth it! Amazing Emma…

Emma Gregory: 2am alarm... 2.30am alarm... 3am alarm... Third time's a charm! Come on Emma! Going to be a few bleary eyed Brits on video calls later on today.

Excellent commitment everyone! Hopefully tonight's entertainment is enough to carry you all through your Friday commitments...

Naomi Broady
British player on BBC Radio 5 Live

I love that she speaks about how she does all the match scouting herself - she loves it. She enjoys the educational side of tennis, so many people leave that to someone else.

She is a sponge, she is learning quickly. We have seen in some of the matches it has taken her two or three games and then she's run away with it.

Canadian Felix Auger-Aliassime, who is into the men's semi-finals where he faces Daniil Medvedev tomorrow, has sent compatriot Leylah Fernandez some nice words on Twitter.

It's nearly time to find out who she will meet for the title. Emma Raducanu and Maria Sakkari are about to head out on to Arthur Ashe!

David Law
Commentator on BBC Radio 5 Live

This is Emma Raducanu's second Grand Slam - it took Serena Williams eight Grand Slam tournaments to do what she is doing now, this is not something that really happens.

Mike Levaggi: It's like 2008 and 2012 all over again, staying up to watch a young Andy Murray in the US Open, desperate to see a Brit win their first Slam. Come on Emma.

Defeating the Olympic champion in a Grand Slam quarter-final was a sensational result for Emma Raducanu - and tonight's opponent Maria Sakkari will offer yet another step up in quality.

In particular, it will likely be Sakkari's serve that will prove the greatest challenge. The Greek won 92% of points on her first serve against fourth seed Karolina Pliskova.

Image source, .

Russell Seymour: Tactical blunder. Woke up too early, and had to watch the first semi. Hanging now!

At 26 years old, Maria Sakkari was the oldest player to reach the US Open final four in the women's draw.

The Greek reached her first ever Grand Slam semi-final at the French Open earlier this year. Now that she's matched that achievement, she'll be hoping to go one further and secure her first shot at a major title.

The 17th seed has recorded some impressive victories to get here, knocking out the fourth, sixth and 10th seeds. She overcame world number four Karolina Pliskova in straight sets in the previous round.

Image source, Getty Images

It will be Raducanu's first taste of a night match on Arthur Ashe, though she has played twice in the grand 24,000 seater stadium during the daytime.

The New York crowd have been right behind the Brit during her remarkable run and it should be a special atmosphere.

James Stevenson: 3am and about to watch a British woman in a grand slam semi-final. It’s a bit mad to tell the truth.

Image source, Getty Images

As is each match she plays at the moment, tonight is by far the biggest match of young Emma Raducanu's career as she steps out under the lights on Arthur Ashe Stadium to challenge the world number 18 Maria Sakkari.

Raducanu said it was a "weird feeling" to have reached the US Open semi-finals and be one of the last few remaining players in the locker room.

"I didn't think I'd be here. But now I am, I'm so excited to get out there," Raducanu said.

"To be in the semi-finals with so few people left in the tournament, it is a weird feeling and I haven't quite wrapped my head around it.

"It'll be my first night match here in New York and it will be a cool atmosphere."

Paul Harper: Well that is one teenager through to the US Open final. Can Emma Raducanu join her? Thank god I had the tactical lie in, this morning, as she won't be on until 3am. COME ON EMMA!!!!

Excited? Nervous? Terrified?

Have you stayed up or did you set a tactical alarm ready to watch?

Do get in touch as we see if Emma Raducanu can become the first British woman to reach a Grand Slam final since 1977.

Image source, Getty Images

A picture that just about sums it up.

Emma Raducanu, the new British number one in waiting, has stunned us all in reaching the US Open semi-finals with some breathtaking performances.

Considering she had her flights back to the UK booked for a fortnight ago, it would appear she's surprised herself ever so slightly too...

Tonight, Greek 17th seed Maria Sakkari stands between the British 18-year-old and a place in her first Grand Slam final.

Are you ready for this?

Now, it's time to see if Emma Raducanu can set up the first all-teen US Open final since 1999.

Here is Leylah Fernandez: "I have no idea! It is thanks to the New York crowd, they have helped me and cheered for me and never gave up for me, they fought for me. Thank you, New York!

"That is years of hard work and tears and blood on court and sacrifices, I really wanted it, I fought for every point, Aryna fought for the same thing and I don't know how I got the last point in but I am glad I'm in the final."

On basketball coach Steve Nash being in the crowd supporting her: "It is a huge inspiration, my dad used him as an example one time for a whole month - so it is an honour to have you here watching and cheering for me. Hopefully we can have a tennis match soon!

"I am going to enjoy my victory and leave everything to tomorrow to worry about the next match, leave my dad to the planning and strategy. I don't care, I just want to play a final right now!"

Naomi Broady
British player on BBC Radio 5 Live

The biggest smile on the face of Leylah Fernandez. Her box must be emotionally exhausted - but they still have one more match to get through.

Aryna Sabalenka congratulates her opponent, the second seed just crumbled in that final game, she disappears while Fernandez sticks around to try and talk the crowd through that win.