Her 7-5, 6-1 victory extended her unbeaten streak on clay this season to 16 matches, only the second woman after Justine Henin in 2005, since WTA rankings began, to notch as many.

“I'm still in shock, you know, to beat such an unbelievable player who won four times here and I lost [three] times to her before this,” Kostyuk said. “So, never taken a set off her, it's incredible. I still cannot believe it.”

On her 25th birthday, the Pole admitted she felt unusually tense and unable to regroup after losing control of the opening set.

In pursuit of her seventh straight quarterfinal in Paris, it all became a slippery slope as the match wore on, a capitulation she said needed to be addressed once the dust had settled.

“It's not great. I know that I lost because I was tense, and my body couldn't really do what my body – the proper things, you know, but it's not the first time,” Swiatek said. “So, yeah, just need to work on it. I feel, like, for sure I lost today because Marta used the opportunity, and I was super tense.

“I feel like I can work on that, at least, and there is a reason, and there is maybe a solution. Maybe it's not going to take one week or one month.

“Maybe it's going to take even a season or something, but I need to believe that I can work through this and not be thrown off so quickly."

Since returning from injury, which drew a line through her February, Kostyuk has been unstoppable on the terre battue.

The 15th seed, who had only reached the last 16 in Paris once five years ago, carried the form from her maiden WTA 1000 title in Madrid and a WTA 250 title in Rouen into the second week in Paris, but denying Swiatek in Paris was her most formidable task of the swing.

While Swiatek had not passed the semifinals in any of her three lead-up events, her record at Roland-Garros spoke for itself – four titles from as many finals, 43 wins from 46 matches.

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Her only defeat before the quarterfinals came against Simona Halep in the fourth round on debut in 2019.

Searching for her second Grand Slam quarterfinal appearance after the Australian Open two years ago, Kostyuk handled the milder, breezy conditions better throughout the one-hour, 40-minute affair to set a last-eight showdown against her seventh-seeded compatriot Elina Svitolina, a later victor over Swiss 11th seed Belinda Bencic.

“I feel like I have given myself more space to just create something, you know challenge my opponents,” Kostyuk said. “And I think the most important thing that I've been doing this whole time is really just trying to enjoy.

“I woke up today in the morning and all I thought about was what an unbelievable day I have to live today and play on Chatrier and play against Iga. There is nothing else I could do today than this. I love it because I want to connect with people. I want to feel this energy.”

After the pair traded three straight breaks, Swiatek had a chance to serve for the opening set, but a wildly sprayed forehand wide and a netted forehand volley though were indicative of her problems as she failed to convert.

➡️ Read: Ukraine's women - 'A great inspiration for the younger generation'

Kostyuk made the most of the reprieve and after reeling off three straight games to take it, she cut a remarkably relaxed figure as the Pole left the court, smiling and dancing along to the music sounding through the arena.

After conceding an early break to start the second set, Kostyuk never wavered again, tearing through the final six games without a hint of nerves.

“I want to keep enjoying, you know. I try not to focus at all on winning or losing because, you know, I'm not playing tennis to win,” she said.

“I'm playing tennis because I love it and because I wanted to connect to people. I want to feel this energy coming to the court and make people happy and unite people.”

In a touching moment in the players’ tunnel beneath Court Philippe-Chatrier, Svitolina gave a smile and a high five as her jubilant countrywoman left the court.

With Svitolina on the cusp of booking an all-Ukrainian showdown, Kostyuk couldn’t help but glance at the live action on an adjacent screen during her post-match press conference.

“I think we have really good relationship. She's a legend of Ukrainian tennis, and, you know, such an honour to share the court with her on Tuesday,” she said.

“Yeah, I mean, she's paved the way for a lot of Ukrainian girls and boys, and she's doing great. And especially this year, she's doing unbelievable.”