Right then, follow that!

That wasn't just good from Keys, it was perfect. Assuming her leg holds out, she and Stephens should give us some final - join me for that on Saturday evening, but not before you've joined us tomorrow for the men's semyes. Night!

I have not the slightest doubt that Keys will serve this out. At 15-all, she hits a loose forehand, but so does Vandeweghe, who nets her next contribution. So she tries a drop shot and Keys misses wildly, but a second serve out wide earns her match point ... sealed with an ace! Keys squeals in delight, the players hug at the net, and what a performance that was! Keys will meet Stephens on Saturday!

Bad start for Vandeweghe as she serves to stay in the match, but Keys then misses with a pass when she comes in and hits a backhand long; 30-15.Next, one of her best points of the match, a big serve and lovely volley of a ball probably going out, and after losing the next point she forces Keys to serve out.

Making an error to give Keys 15-all, Vandeweghe gently breaks her racket, and isn't penalised for changing it. There's no need really, it's very soon 40-15, Keys raising that game point despite an excellent return. Vandeweghe saves one, then sets up her big forehand, only to contact the top of the net. For the first time, she shouts her displeasure.

She's back...

Anyway, Keys goes off, leaving Vandeweghe alone with her thoughts.

Keys calls a medical timeout. She clearly hasn't considered how late/early it is in England. Selfish imo.

Keys must be hurting because why else ask for help at this point. But she keeps thrashing away - she has such a strong base - and the pressure sees Vandeweghe miss an easy volley then net a backhand; 30-40, and if this goes, we can pretty much go home. But Vandeweghe finds a serve! It doesn't matter! Keys gets advantage, and pastes an absolute jazzer of a backhand return into the far corner! She's nearly there!

Vandeweghe really has no answer to Keys here, who's hitting the ball so well, not just in terms of power but also length and direction. But a big forehand return, cross-court, gets 30-15 - by the standards, a chance. And there's another good one for 30-all, not a winner but enough to elicit an error, so Keys sends down a service winner only to hit the net with a backhand; deuce. But that's as good as it gets for Vandeweghe, who saves a few game points but can't record any break points. But Keys calls for the trainer, her right leg hurting apparently.

Serving at 15-30, Keys hits a backhand long - she's playing with so much confidence that she's going for everything, so if Vandeweghe can just have her do that on her own serve, she has hope. But at 40-30 she comes in off a half-arsed approach, forced to stand there and wait to be passed, which she is. Then on deuce, a perfectly-measured return has Vandeweghe hitting the net with a forehand and through the next rally she tries some backhand slices, only for Keys to supply her own power, sealing the break with a forehand into the corner! This is a perfect performance so far, it really is.

That hold for Vandeweghe puts no pressure on Keys whatsoever; she holds to love, sealing things with a second-serve ace.

Vandeweghe must hold here, but Keys carries on as before, winning the first point of the game ... and the second when Vandeweghe nets a backhand. But a good volley arranges 30-15, and unlike against Rybarikova, Vandeweghe is holding it down, staying dispassionate and holding well.

Keys gets to 40-15, at which point Vandeweghe hits her best return of the match, cross-court and into the corner. Keys still serves out - completing perhaps the best set she's ever played - but there's a small shard of light for her opponent.

It never rains. At 15-0 Keys slides into a forehand and gets the net cord, but Vandeweghe serve-volleys again to win a rare point; perhaps that's her route to victory, and if not, improvement. Anyhow they end up at deuce and Keys then pounces on a loose volley to angle a squash-shot cross-court; set point, in 18 minutes. Vandeweghe saves it, and eventually closes out to save the bagel, get on the board, and perhaps nab some momentum.

At 4-0 a glimmer for Vandeweghe, who returns well and puts away a volley. Keys responds with an ace down the middle! 5-0, 13 minutes.

Vandeweghe 0-4 Keys

One-way traffic here, Kes handing out an absolute pasting. Two more winners, eight so far for two points lost, get her 0-30 before she nets and gives Vandeweghe a glimpse. But a long forehand gives her two points for the double break and Keys catches her next return perfectly, a backahdn down the middle and right onto the line; Vandeweghe ca only net, and she's absolutely reeling here.

Vandeweghe 0-3 Keys

Another love hold for Keys who is 3-0 ahead after just six minutes on court. She's taken no time at all to find her groove; her match against Svitolina might just be the turning point in her career.

Keys gets to 15-30 with a strong backhand return, and when Vandeweghe slices and comes in, she passes her cross-court, and easily; two break points. The first is saved via strong serve but the second converted, a low return forcing the error.

Quick start for Keys and Vandeweghe doesn't really get to feel the ball on her racket, which makes her decision to receive not such a good one. A love hold, with Keys hitting it beautifully.