American teenager Coco Gauff says she is feeling “emotionally fresh” as she reached the US Open semi-finals for the first time by beating Jelena Ostapenko.

The 19-year-old will now face French Open runner-up Karolina Muchova for a place in the final.

“I think the problem in the past in Grand Slams is that I would emotionally be drained,” sixth seed Gauff said.

“Now I’m physically fresh and emotionally fresh, and I think that just came from experience.”

Another victory would put Gauff into the second major singles final of her career, matching her run at the 2022 French Open when she was beaten by Poland’s Iga Swiatek.

There has been a different aura about Gauff following a successful North American hard-court swing where she won two of the WTA Tour’s biggest titles in Washington and Cincinnati.

Since a chastening first-round exit at Wimbledon, Gauff has turned her form around with the help of new coach Pere Riba and consultant Brad Gilbert.

The teenager has won 16 of her 17 matches since losing at the All England Club in early July.

Gilbert, who has coached Andy Murray and Andre Agassi among others in a successful career, has been the focus of a lot of the attention and Gauff credited him for helping her enjoy her tennis more.

“I wish I embraced the fun parts a little bit sooner,” said Gauff, who was left in tears when Ostapenko beat her in the Australian Open fourth round earlier this year.

“I thought to play and win you have to be ultra serious and ultra focused, which that is true, but also you still have to enjoy it.

“I think that’s what’s been the change is that I’m having more fun.

“One of the first things Brad said is ‘you need to smile more’, it wasn’t really anything with my game.

“That’s something I’m trying to work on and continuing to do, and obviously I think it’s helping my results.”

Ostapenko criticises ‘crazy’ scheduling

Gauff had seen three of her first four matches at this year’s US Open go to a deciding set, including her comeback wins against Germany’s Laura Siegemund in the first round and Belgium’s Elise Mertens in the third round.

Following a much quicker win over Ostapenko, Gauff she was “proud” of coming through what she described as “one of the harder runs” she has faced at Flushing Meadows.

After only nine minutes of action in Tuesday’s opening match on Arthur Ashe Stadium, Gauff had raced into a 3-0 lead with a double break of serve.

Ostapenko, who knocked out world number one Swiatek in the last 16, made 10 unforced errors as her boom or bust approach malfunctioned.

After dropping only seven points in a 20-minute first-set demolition, Gauff broke Ostapenko’s serve in the first game of the second set.

Ostapenko did immediately break back for her first game of the match, only for Gauff to regain control a few minutes later and quickly turn a 2-1 lead into victory.

Afterwards, 26-year-old Ostapenko complained about the scheduling of the match, which started at 12:00 local time on Tuesday.

Her victory over Swiatek was completed just before midnight on Sunday and the Latvian said she had been told to expect a late start against Gauff.

US Open organisers denied that had been the case.

“When the schedule came out, I saw I’m playing first match and was like ‘wow, that’s a little bit strange scheduling’,” said Ostapenko.

“I think it’s really hard to recover from those night matches, because after beating the world number one I went to sleep at 5am.

“I got back to the hotel around 2am and even [though] I tried to go to sleep at 3am, I had all this adrenaline and it was impossible to fall asleep.

“Then when you go to sleep at 5am or 6am, you need a few days just to recover. I think it’s a little bit crazy.”

Muchova’s fine run continues

Czech 10th seed Muchova continued her fine run at the US Open as she beat Sorana Cirstea of Romania 6-0 6-3 to reach the semi-finals for the first time.

Muchova was ranked 235th in the world when she played at Flushing Meadows last year as she made her way back from an injury lay off.

But she arrived at this year’s event inside the top 10 and progressed to the last four with impressive ease, beating an opponent who had knocked out Elena Rybakina and Belinda Bencic on her way to the quarter-finals.

Muchova dominated the first set, saving all nine break points that she saved, before coming back from a break down in the second to see off Cirstea.

“Unbelievable. This is a really sweet victory. Incredible,” Muchova said.

“I want to enjoy this win and then I will try to put up a battle against Coco.”