Serena Williams crashes out of US Open in 'stunning' turnaround

Victoria Azarenka has produced an extraordinary comeback to make the US Open final and send Serena Williams packing.

Chasing Margaret Court’s grand slam record of 24 major titles, Williams looked well on her way to the final against Naomi Osaka when she won the first set 6-1 on Thursday.

However Azarenka produced a stunning turnaround to take the second and third sets from her visibly frustrated opponent.

‘RIDICULOUS’: Fans erupts over shocking Serena Williams tweet

‘2014 VIBES’: Eugenie Bouchard stuns with 'special' display

Azarenka was a completely different player as she overpowered Williams across the final two sets, while the American appeared a shadow of her first set-self.

Williams appeared to suffer an ankle injury early in the third set, calling for the doctor and taking a medical timeout.

But the break couldn’t disrupt Azarenka’s momentum, who prevailed 1-6, 6-3, 6-3.

TV commentators described Williams’ inability to close out the match after winning the first set “stunning.”

It marks the first time in seven years that Azarenka will play in a grand slam final.

“It's been seven years? That's my favourite number,” Azarenka said.

“I guess that's meant to be. I'm very grateful for this opportunity.

“On the road to the final, you have to beat the best players and today was that day.

“It was mentally one of the strongest comebacks I’ve done. I had to get myself out of really big trouble.

“At this stage of a grand slam against Serena, I know she’s not going to give away anything. In that way it’s one of the best matches I’ve played.”

Williams led Azarenka 18-4 in head-to-head matches and had won all 10 of their previous grand slam encounters - including the 2012 and 2013 US Open finals.

Williams, who turns 39 in less than three weeks, remains one shy of a record-tying 24th grand slam singles title.

Naomi Osaka awaits in US Open final

Osaka reached the US Open final for the second time in three years after she overcame American Jennifer Brady in a three-set slugfest.

Osaka prevailed 7-6 (7-1) 3-6 6-3 in two hours and eight minutes to advance to Saturday's final - where the 2018 champion will meet Azarenka.

“It means a lot for me. I kind of consider New York my second home,” Osaka, who was born in Japan and moved to the United States as a child, said.

“I kind of love the atmosphere, even though there’s no people here. I feel like this court kind of suits me well.”

Thursday's match against Brady under the roof at Arthur Ashe Stadium swung when Japanese fourth seed Osaka got her only break of the match to take a 3-1 lead in the third set.

Brady arrived at her first major semi-final without having dropped a set in New York and did not show any nerves but Osaka's firepower allowed her to get by the 28th seed in a high-quality match.

Osaka continued her tradition this tournament of coming onto court wearing a face mask displaying the name of a black victim of violence to highlight racial injustice.

Playing for a cause bigger than herself has given Osaka a clear mindset and she played accordingly, firing 35 winners and just 17 unforced errors against Brady.

with AAP