As the Great Britain and Australian teams lined up ahead of their highly anticipated United Cup tussle, Alex de Minaur and Katie Boulter savoured the last moment of peace in their household for the day, greeting each other on-court with a friendly kiss on the cheek. Then they retreated to their opposite corners of the arena and prepared to do battle.

By the end of the night, De Minaur had claimed victory in their skirmish but Boulter and her team were triumphant in the war. Although Australia defeated Great Britain 2-1 in Sydney, the home nation was knocked out of the competition as Great Britain advanced to the quarter-finals of the United Cup.

Britain knew one straight-sets success from three rubbers would be enough to see them top the group and Boulter opened the tie by clinching the first rubber with a dominant 6-2, 6-1 win over Olivia Gadecki. De Minaur pushed back with an identical 6-2, 6-1 dismantling of Billy Harris. In the decisive doubles rubber, De Minaur paired with Gadecki to close out a 6-3, 7-6 (3) win over Olivia Nicholls and Charles Broom but their victory was not enough to see them through to the knockout stages.

The British team will have no time to enjoy an impressive result considering the absence of the British men’s No 1 Jack Draper. They will return on Thursday to face Iga Swiatek’s Poland for a place in the semi-finals after Poland narrowly defeated the Czech Republic 2-1 on Wednesday.

A year ago, the United Cup set the tone for the best season of Boulter’s career as she won both of her singles matches and clinched her career best win over No 5 Jessica Pegula in the competition. She has started the new year in a similar fashion, striking the ball cleanly and playing high-octane, decisive tennis.

Although Gadecki is a talented young player with powerful strokes when she has time on the ball, Boulter smothered her from the very beginning. She rushed the 22-year-old with relentless aggression and depth, serving well and maintaining her high intensity until the end.

Even as Boulter celebrated an excellent individual performance, De Minaur remained on her mind: “Very happy to start my new year like that. I feel like I have lost a lot of sleep recently over the thought of playing my fiancé in mixed doubles so I’m so tired,” she said, laughing. “I’m just very happy to get through this rubber, I’m not going to lie.”

Like Boulter, De Minaur is playing the best tennis of his life and his 2024 season marked a significant moment in his career as he reached a career high ranking of No 6 despite struggling with a hip injury in the second half of the year. He is also the leader of his team. Unsurprisingly, De Minaur pulled Australia back into contention with an excellent performance.

Having clinched Great Britain’s spot in the quarter-finals regardless of the final result Boulter opted to sit out the mixed doubles, preserving her energy and avoiding a direct tussle with De Minaur. While Britain had defeated Argentina in their opening tie on Monday, Australia paid dearly for their loss to Argentina in the group. They entered the mixed doubles with the incredibly difficult challenge of losing no more than four games in order to advance as the best performing runner up of the two groups competing in Sydney. Despite de Minaur’s admirable efforts, they fell short.

“It was great, I enjoyed every second we had here on this Sydney court,” said De Minaur. “I enjoyed playing mixed with Liv a lot. It was a lot of fun, great atmosphere. We did our best.”

Less than 24 hours after clinching Britain’s semi-final berth, Boulter will return to the same court for one of the biggest challenges in the sport as she faces an in-form Swiatek in their first meeting. This time, she will at least be able to count on the unwavering support of her future husband from the stands of the Sydney Olympic Park after spending the first day of the new year as mortal enemies.