“Oh, wow”.

That was Coco Gauff’s surprised reaction when she learned she was part of a US Open semi-final line-up that has not been seen in more than half a century.

For the first time since 1975, the top four seeds in the women’s singles draw have reached the semi-finals at the New York major.

Now, 51 years later, the stars have aligned once again with Aryna Sabalenka, Elena Rybakina, Jessica Pegula and Gauff all surviving three-set thrillers to create a semi-final line-up for the ages.

“How amazing – it doesn’t get much better than that does it?,” former British number one Annabel Croft told BBC Radio 5 Live.

“It has felt fantastic the whole tournament – I just feel like I’ve been more enthused about looking forward to the match-ups this Grand Slam than any I can remember.”

It is the first time the top-four ranked players have reached the women’s semi-finals at any Grand Slam since Wimbledon in 2009, and it hints at a shift away from the unpredictable landscape that has characterised the women’s game in recent years.

Since the start of 2020, there have been 13 different Grand Slam women’s singles champions – compared to just seven on the men’s side.

“I just feel like there’s lots of really big names now, big personalities going up against each other and it’s really exciting,” Croft added.

“We’ve been blessed with the amount of intriguing matches we’ve had. You’re seeing these warriors out on court.”

Top seed and two-time defending champion Sabalenka will face American Pegula in Thursday’s first semi-final (00:00 BST, Friday), while Rybakina – who will replace Sabalenka as the new world number one on Monday – takes on fourth seed Gauff afterwards.

While Sabalenka is bidding to become the first woman since Serena Williams in 2014 to win three successive US Open titles, Pegula is the only player remaining in the women’s draw still chasing a maiden Grand Slam.

The pair need no introduction to each other, having faced each other 13 times.

That includes the past two US Open tournaments, when Sabalenka denied Pegula a first major title in the 2024 final and fought back to win in last year’s semi-finals.

“It’s fun to look at it like a rivalry. I think that’s what motivates me,” said Pegula.

“I know that she’s definitely pushed me to become a better player, so I always respect and appreciate that aspect of our rivalry.”

Pegula, who has got the better of Sabalenka on four occasions on the WTA Tour, said beating the four-time major winner at Grand Slam level is a “hurdle” she must overcome.

Sabalenka, meanwhile, said she was “super excited” to face Pegula, who arrived in New York in better form after reaching the final in both Washington and Cincinnati.

“I’m loving playing against her because it’s a battle, because it’s a fight, and I love being under pressure and going through tough challenges,” said Sabalenka, who is into her first semi-final since falling to Pegula at June’s Berlin Open.

“I know she hasn’t maybe had the best results this summer, but I know that she has a lot of confidence playing here at this tournament, and she’s going for a three-peat,” Pegula added.

By reaching the semi-finals, second seed Rybakina will become the new world number one on Monday – ending Sabalenka’s 99-week reign at the top.

But the second seed has described the top ranking as “just a number” and stressed that her focus remains focused on winning her third Grand Slam title.

“It’s never quite the same if you become world number one having lost a Grand Slam final or semi-final just beforehand, so she will be trying to cap off an absolutely perfect couple of weeks by winning the title,” tennis correspondent Russell Fuller said on BBC Radio 5 Live.

Standing in her way, however, is Gauff, who will have the home crowd’s backing on Arthur Ashe Stadium.

The 22-year-old American, who won the Flushing Meadows title in 2023 but suffered fourth-round exits in the following two years, said she has a different perspective to this year’s tournament.

“Sometimes you’re just so focused on the now, now, now, because you want it now, and obviously you want to take advantage of your opportunities,” she said.

“In the grand scheme of things, [I’m] definitely sitting here in a different mindset and perspective than I was last year.

“It inspires me a little bit more to keep working, as I see how much I have improved in a year.”

Gauff leads the head-to-head 2-1, but Australian Open champion Rybakina fought back from a set down to triumph in last month’s Canadian Open semi-finals.

“I’m going to have some aces hit on me and some winners hit on me, but I’m going to keep fighting and give it my all. That’s all I can do,” Gauff said.