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So, the all-American semi-finals has been boiled down to the all-American final and it is the younger generation who will contest the title with Sloane Stephens going up against Madison Keys.

Given their shot-making today, it should be a hum-dinger.

First, though is the men's semi-finals.

Pablo Carreno Busta takes on Kevin Anderson in the first from 21:00 BST before Juan Martin del Potro and Rafael Nadal take to the floor.

It could be a long one. It will certainly be a good one.

Join us then.

Madison Keys: "It still doesn't feel real. I'm still shaking. I played pretty well tonight. There are a lot of things in my head right now, so I'm struggling to come up with words.

"I knew had to rise to the occasion and I'm just really happy to be in the final."

On leaving the court for treatment: "I definitely started to feel it and was worried something more serious could happen, I felt like I needed it worked on sooner rather than later. I feel great right now, I don't think I could feel better than I do right now."

On facing Sloane Stephens in the final: "Sloane is a new person right now. She is really loving being out on the court again. She's playing really well and I'm excited we get to play each other in a US Open final. It's pretty cool to say."

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

That was an incredible performance from Madison Keys. It's got to be a difficult situation for Coco Vandeweghe, but she handled the last embrace leaving the court.

Madison just played really, really well today.

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The two players share a warm embrace at the net.

Coco Vandeweghe is not hanging around long though.

She stalks off down an Arthur Ashe corridor and back to the solitude of the dressing room where a meeting with her own mind awaits.

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

That's what is so beautiful about tennis, it can change when you're not expecting it to. But you would expect Keys to close out this match.

She's not going to want to get into long rallies. So we'll see.

Coco Vandeweghe bashes away a forehand to hold to 30.

But she looks like she knows her chance of a first Grand Slam final has gone.

She tosses her bat onto the chair next to her as he takes her stool.

Madison Keys to serve for a place in the final and a Saturday rendez-vous with Sloane Stephens next.

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

Even if Madison Keys does have a little inkling of an injury, she is lucky she has that big serve to back it up.

All the emotion we have seen from Coco Vandeweghe has been negative. Even if you can feel one positive thing for a moment... she's not taking any positive energy away from anything.

Madison Keys keep clonking winners like with the gleeful abandon of a kid playing whack-a-mole at a village fete.

Coco Vanderweghe looks like she has murder on her mind. One racquet has already been broken by the brunt of her frustration.

Frankly, she looks like she could wreck a whole hotel room.

Vandeweghe serves to stay in the match next.

Image source, Reuters

Madison Keys is back. She is walking freely, but then she was before she went off for treatment.

Let's see how she goes.

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

Madison is having her back checked. A lot of times when something has happened to your knee, they check your back. If your hips are out of alignment it can affect your knee.

Coco hasn't had many opportunities to mix it up. She's trying to. But to try a drop shot off the pace of Madison Keys is not easy to do.

Vandeweghe, you would think the best strategy would be to try and move Madison Keys. But you can't always be consistent against someone that annihilates every ball off the ground.

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Madison Keys strides off behind the scenes for treatment.

Whatever little strain she is getting work on, does not seem to be affecting her too much.

She is still moving well on court.

But surely she would want to keep the pedal to the metal rather than risk losing her momentum?

Coco Vandeweghe plonks her backhand into the net to offer up a break point at 30-40.

A second break here and surely she might be ready to amputated from the tournament.

Vandeweghe sees off that danger with a bit of old-school serve and volley.

But there is no escape.

Madison Keys rips a bullet backhand done the line, leaving Coco in the traps as it skids away for a clean winner.

Image source, Getty Images

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

This game from Coco has been angry. She's going after her shots, but it's actually paying off.

Madison Keys wraps up the game.

She is within sniffing distance of a first US Open final.

But what's this? Keys seems to ask the umpire to call the trainer for a leg tweak as the balls head up to Coco's end of the court.

Could that derail her express progress towards the final?

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Madison Keys is not dominating like she did in the first set.

Indeed Coco Vandeweghe has managed to nudge her way to deuce.

She could really do with this...

Coco Vandeweghe launches a volley of inventive towards her camp in the players' box.

That might be her most powerful and precisely aimed shot of the afternoon so far.

Will that frustration-busting free hit at punchbag coach Pat Cash ease out the wrinkles in her game?

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

Every single time Vandeweghe has done a good job of digging that first volley out, she can't get enough on it and she is giving Madison time to play the passing shot.

Coco has that look of being unsure when she's setting up for the ball. That's what happens when you're nervous. Your feet slow down, your strokes slow down.

She's extremely frustrated, trying to regroup.

Image source, Reuters

Coco Vandeweghe wafts a couple of awkward forehands into the net to offer up break point.

A bad case of the jitters for the 25-year-old.

She is prodding at the ball rather than striking it.

And Madison Keys takes advantage, flaying away the winner.

A double fault from Coco Vandeweghe puts her in a spot of 15-30 bother, under serious fire from Madison Keys, she tip-toes to deuce.

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