Here is a lifeline.

Madison Keys, nothing to lose suddenly, is slugging and, for all her chasing, Sloane Stephens can't keep up.

0-40 and three break points for Keys.

Image source, AFP

Jill Craybas
Former world number 39 on BBC Radio 5 live

Keys just hasn’t mentally regrouped after that first set. Sloane has been completely steady throughout this match.

Madison Keys rescues two break points, but double faults on the third!

Agonising.

She tears off a wristband and hurls it to the floor in frustration.

Image source, Getty Images

Sloane Stephens is seeing the ball as big as a balloon.

Nothing is landing for Madison Keys.

0-40, three break points and, you might well say, three virtual match points.

Madison Key cuffs a return wide at 30-30 and, as she marches back across court to receive the next serve, there looks to be a little wobble in her bottom lip.

She gets a look at a second serve. Again, she misses with her return.

Seeing the biggest match of her career slipping away from her, apparently hindered by her leg injury, this could get very ugly.

Jeff Tarango
Former professional tennis player on 5 live at Flushing Meadows

Keys is not settling in, not comfortable with the thought of her becoming a Grand Slam champion and Sloane is tasting the appetisers of it.

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Madison Key salvages two break points, but her charge to the net in pursuit of the third is ill-advised.

Stephens has too much time on the ball, the angle is too inviting and she can't get close enough to the wire to close down the cross-court option.

The ball fizzes past her groping racquet and in.

This might well be the beginning of the end for Keys.

Argh.

A horror show of a drop volley from Madison Keys as she tries to hide the ball away from the roving Sloane Stephens and plonks it between the tramlines for 0-30.

A searing pass down the line leaves Madison Key flopping in frustration at the net and three break points adrift.

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Sloane Stephens gets to make the pace, serving first in the second set as well.

Madison Keys has a chance to turn around that reality at 30-30, but thrashes a very makeable return into the top of the net.

She berates herself.

But maybe the chance is not gone. Deuce.

It is now. Stephens holds on, luring another couple of errors from Keys.

Jeff Tarango
Former professional tennis player on 5 live at Flushing Meadows

Madison's negative body language throughout this first set has dictated it. She needs to play a lot more positive tennis, she’s in the final.

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Sloane Stephens is just not being ruffled by Madison Keys.

Maybe the sledgehammer power is missing. Maybe Keys is playing it safer after flirting with the lines too much. Maybe Stephens fetching and scurrying is just nullifying those weapons.

Whichever way it is not working for Keys.

Seventeen unforced errors for her. And a forehand long over the baseline sees her fold out of the opener.

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Madison Keys grimaces and grips her thigh after leaping into a groundstoke.

Is that quad strain starting to catch up with her?

She needs to be firing on all cylinders at 30-30.

Sloane Stephens gives her a taste of her own medicine with a whopping forehand down the line that streaks through the paint for set point.

Keys makes it to deuce, coming out on top in a mutually twitchy rally.

Sloane Stephens is stalking down the opening set in impressively cool style.

She is landing with a high 70% of first serves and winning 86% of points behind that initial tee-off.

Those numbers are hard to argue with and even harder to break serve against.

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

I don’t feel Keys is hitting with as much power as she did in her previous matches.

I wonder if it’s related to the strapping on her leg from the previous match. I wonder if she’s not able to push off it.

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We are now two years past the date that Marty McFly travelled to in Back to the Future Two, but here is Michael J Fox having to tie his own laces and skateboard on boring old terra firma.

Biff would have made a fair bit of cash had he plonked his cash on this as a US Open final before the start of the fortnight.

Anyway, Keys manages to wrestle her way to the game, holding to 30.

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Emma Stone is here too.

I haven't seen La-La Land though so I'm not sure if there is anything I can tediously and tangentially relate to this match in that one.

Image source, AFP

Jeff Tarango
Former professional tennis player on 5 live at Flushing Meadows

This is judgement day baby. That is why the crowd is so quiet, they're studying. They’re seeing who do I like more, who do I want to follow over the next few years and who has the better smile.

Is Sloane Stephens' battery bunny movement starting to mess with Madison Keys' head?

Keys is pulling the trigger early and ambitiously in rallies attempting to blow her opponent off the court.

She is having to trim her margins though and she misses her mark to lose the opening point.

But that is better from Keys - she drags Stephens out of court and wallops away to 15-30.

But the confidence and accuracy that swept Coco Vandeweghe aside in the semis is not quite there.

Another two shots buried into the net and Stephens slips out of trouble.

Jill Craybas
Former world number 39 on BBC Radio 5 live

Both players look to be a little more defensive than they have been in their previous matches. They seem to be just feeling their forehands in the beginning of this match.

Now then.

The first glimmer of a chance against serve as Madison Keys picks the wrong ball to go big on and plants wide to give Sloane Stephens 0-30.

A sweeping backhand across court repairs some of the damage, but Keys sprays wide again to offer up 15-40 and two break points.

Stephens only needs one.

She lures Keys long to go a break up.

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Sloane Stephens knocks off her second service game to love.

Very nice work and she casually kicks her heels up into her buttocks as she stretches off in celebration at the back of the court.