Coco Gauff came through a three-hour battle with Ukraine’s Marta Kostyuk to reach the semi-finals of the Australian Open for the first time.

The US Open champion had cruised through to the last eight but was pushed very hard by first-time grand slam quarter-finalist Kostyuk before clinching a 7-6 (6) 6-7 (3) 6-2 victory after three hours and eight minutes.

Gauff trailed 5-1 in the opening set before fighting back to win it, saving two set points.

She served for the match at 5-3 in the second set but now it was Kostyuk’s turn to surge back, and it was not until the third set that Gauff took control of the match, opening up a 5-0 lead.

The 19-year-old is the youngest American to reach the women’s semi-finals in Melbourne since Mary Joe Fernandez back in 1991, and she is now two wins away from making it back-to-back slam titles.

If she is to achieve that, she will surely need to play at a consistently higher level than here, with the pair making a combined 107 unforced errors.

“It was a fight,” said Gauff. “I think today was definitely a C game, so I didn’t play my best tennis, but I’m really proud that I was able to get through today’s match. Hopefully got the bad match out of the way and I can play even better.”

Kostyuk, 21, was immediately able to put the result into perspective, saying: “I think it’s just a tennis match. I’m here to grow, to learn, to be better.

“I’m very proud of myself. I won for myself today, and I think it’s the most important thing. It’s just the beginning of the season. I’m looking forward for what’s ahead.”

Kostyuk and countrywoman Dayana Yastremska both made the last eight – Yastremska may yet go further – while Elina Svitolina reached the fourth round, and all have used the opportunity to highlight the ongoing plight of Ukraine.

“I think the girls did really well,” said Kostyuk. “I hope we will be able to succeed in most of the tournaments, especially the big ones where there is a lot of media. I think people should be reminded.

“I was texting with some people from Kyiv. I said, ‘How is it? How are you guys?’ They said, ‘Well, we were looking between your score and where the missiles are flying. So it’s still there. My parents are still there. My sister is still there.”