Over the course of the past 18 months, by far the most rewarding period in her blossoming career, Katie Boulter has gradually established herself as one of the best players in the world. She has won noteworthy titles, defeated top opponents and embedded herself inside the top 30.

Yet no battle in her career has quite matched the delirium of an unforgettable night in Sydney when she went shot-for-shot with the greatest active women’s player, Iga Swiatek, and came so close to securing her biggest victory yet. After three hours of tennis of the highest ­quality, Swiatek somehow survived a brilliant ­performance from Boulter, winning 6-7 (4), 6-1, 6-4 to secure a 2-0 win for Poland over Great Britain and a spot in the semi-finals of the United Cup.

Earlier on Thursday, Britain’s Billy Harris played a solid match but he was outclassed by the men’s No 16, Hubert Hurkacz, who closed out a tough 7-6 (3), 7-5 win to secure Poland’s first victory of the tie.

“I’m just exhausted, you know?” said Swiatek, the world No 2. “I’m happy that I won so I don’t need to play mixed doubles. This match was crazy. So many changes of momentum. I thought I had it under control in the first set but for sure I got tight and didn’t work on it. But then I did not want to repeat the same mistake in the third.”

Having finished her 2024 season by reaching a new career high ranking of No 23, Boulter started the new year in strong form, registering two dominant wins over lesser opponents as she led Great ­Britain out of their round robin group despite the late withdrawal of the British men’s No 1, Jack Draper.

Her reward for those efforts was a shot at Swiatek, one of the great challenges in the women’s game. It took just a few minutes for Boulter to understand the task before her as Swiatek exerted immense pressure from the very first game. Every time Boulter’s rally ball dropped short or slowed, Swiatek pounced. In the blink of an eye, the Pole had established a 4-1 lead.

Fully aware that only her best level would suffice, Boulter responded superbly. She recovered the early break with an exemplary exhibition of first-strike tennis, desperately looking to take the initiative as early as possible and injecting massive pace into every groundstroke. As she levelled the set at 4-4, Boulter’s average forehand and backhand speeds read 76mph and 75mph respectively.

By the time they reached the first set tie-break, Boulter simply could not miss as she took control of every point and put Swiatek under suffocating pressure. After opening the tie-break with two searing forehand winners, she ended it completely on fire, pummelling three consecutive backhand winners from 4-4 to seize the opening set.

Unsurprisingly, Swiatek responded immediately. She took full advantage of Boulter’s drop in intensity at the beginning of the second set, breezing through 6-1. Boulter gathered herself at the beginning of the final set and made the first move, breaking serve for 2-1 as Swiatek took a medical timeout. Even when Swiatek pulled her back on serve, Boulter continued to battle hard. She pulled out a stupendous service hold for 4-4 after saving two break points.

“I took four painkillers because a lot hurt but I’m happy that we won and, for sure, I’m going to use the day off tomorrow,” said Swiatek.

With the quality of ball striking from both players continuing to rise deep in the final set, this spectacular contest, an early contender for one of the best matches of the year, came down to a moment of total brilliance from a determined Swiatek. Down break point at 4-4 with the match hanging by a thread, Swiatek scuppered Boulter’s huge opportunity with an outlandish backhand down-the-line winner that barely clipped the edge of the line. Then she locked down her game and refused to miss, winning the final seven points to close out a memorable win.

“I tried to keep pushing, knowing that I need to keep up the quality because with quality I know I’m not going to play the longer rallies if I’m more precise,” said Swiatek. “It’s hard to be precise under so much pressure. But I made it today. For sure, it’s a step forward.”