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NOW: Britain's Emma Raducanu beats Greek 17th seed Maria Sakkari 6-1 6-4 in US Open semi-finals
Raducanu, 18, becomes first British woman to reach Grand Slam singles final for 44 years
Earlier: Canadian teenager Leylah Fernandez beats Belarusian second seed Aryna Sabalenka 7-6 (7-3) 4-6 6-4 to reach final
Fernandez 7-6 (7-3) 4-6 6-4 Sabalenka
Leylah Fernandez's fairytale run continues!
Aryna Sabalenka dices long and the 19-year-old wins this semi-final with her first match point.
She's into the US Open final!
Fernandez 7-6 (7-3) 4-6 5-4 Sabalenka*
A second double in succession! Three match points for Leylah Fernandez.
Russell Fuller
Tennis correspondent on BBC Radio 5 Live
Sabalenka started so well in this match but for all her brilliance the consistency is lacking and we just have to admire the way Leylah Fernandez is playing.
Fernandez 7-6 (7-3) 4-6 5-4 Sabalenka*
Wow. That was a wayward double fault, never even threatened to land in. 0-30.
Fernandez 7-6 (7-3) 4-6 5-4 Sabalenka*
So Aryna Sabalenka, serving to stay in the tournament...
She drives the first backhand into the tape. 0-15.
Fernandez 7-6 (7-3) 4-6 5-4 Sabalenka*
A clenched fist in celebration from the 19-year-old. She takes the hold and is one game away from a place in the US Open final.
*Fernandez 7-6 (7-3) 4-6 4-4 Sabalenka
Box office again. Fernandez catches the tape. Sabalenka can't put her away with the volley and eventually the Canadian takes the point. She volleys down a winner on the next, keeping it just inside the baseline, and then flirts with the chalk off a superb ace. Before a double fault...
*Fernandez 7-6 (7-3) 4-6 4-4 Sabalenka
Fist pumps from Sabalenka after getting her reward at the net, and she holds when Fernandez hooks wide. It's all square in the final set.
Russell Fuller
Tennis correspondent on BBC Radio 5 Live
Increasingly in the Grand Slams, Sabalenka is getting nearer to a final. She's been working with a sports psychologist for a number of years and it looks like it's paying off.
She's slowly getting there, but there are also times when you think 'goodness me, this is the world number two - how can she play a shot like that?'
Fernandez 7-6 (7-3) 4-6 4-3 Sabalenka*
You think Sabalenka is about to motor to a quick hold after a string of ferocious serves but then a ball comes soaring back past her off the strings of Fernandez. And there goes another... 30-30.
Fernandez 7-6 (7-3) 4-6 4-3 Sabalenka*
And this time the second seed gets it.
Aryna Sabalenka leaps all over a second serve with a thunderous forehand winner.
We're back on serve.
Naomi Broady
British player on BBC Radio 5 Live
It's difficult for Emma Raducanu to know when to warm up. It's so difficult as tennis players sometimes to know when you're going to play.
*Fernandez 7-6 (7-3) 4-6 4-2 Sabalenka
Sabalenka will get another go!
After a gruelling baseline exchange, she throws everything into a backhand winner and it screams down the line.
*Fernandez 7-6 (7-3) 4-6 4-2 Sabalenka
A leaping, swinging second serve and Fernandez has saved three break points! Deuce.
*Fernandez 7-6 (7-3) 4-6 4-2 Sabalenka
Oh wow.
Under the pressure of three break points, Leylah Fernandez shows the cutest of touches to delicately lift the ball over the tape and leave her opponent swiping at thin air.
Aryna Sabalenka fires the next break point wide and shouts at herself in furious fashion.
One to go...
*Fernandez 7-6 (7-3) 4-6 4-2 Sabalenka
Punchy stuff from Sabalenka. Fernandez finds the net and the second seed has three break points.
*Fernandez 7-6 (7-3) 4-6 4-2 Sabalenka
Fernandez looks for the disguised forehand but leaks it slightly too wide. 0-30 and Sabalenka senses a chance to hit back immediately.
#bbctennis
S.Mooro: Anyone feeling even more nervous the longer we’re having to wait for Emma Raducanu to start?
Naomi Broady
British player on BBC Radio 5 Live
The crowd are not really against Sabalenka but they're not really with her.
Out there on Arthur Ashe Stadium, that's a lot of people cheering for your opponent.
*Fernandez 7-6 (7-3) 4-6 4-2 Sabalenka
And this time the teenager gets it!
Leylah Fernandez reads the serve, makes it all kinds of awkward from Aryna Sabalenka and the second seed drives long.